Vulnerability-Lookup

CERTFR-2026-AVI-1117

Vulnerability from certfr_avis - Published: 2026-09-04 - Updated: 2026-09-04

De multiples vulnérabilités ont été découvertes dans le noyau Linux d'Ubuntu. Elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur.

Solutions

Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation).

None

Impacted products

	Vendor	Product	Description
	Ubuntu	Ubuntu	Ubuntu 20.04 ESM
	Ubuntu	Ubuntu	Ubuntu 18.04 ESM

References

Title

Publication Time

CVE-2026-53359 (GCVE-0-2026-53359)

Vulnerability from cvelistv5 – Published: 2026-07-04 11:51 – Updated: 2026-08-17 04:50

Title

KVM: x86: Fix shadow paging use-after-free due to unexpected role

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix shadow paging use-after-free due to unexpected role Commit 0cb2af2ea66ad ("KVM: x86: Fix shadow paging use-after-free due to unexpected GFN") fixed a shadow paging mismatch between stored and computed GFNs; the bug could be triggered by changing a PDE mapping from outside the guest, and then deleting a memslot. The rmap_remove() call would miss entries created after the PDE change because the GFN of the leaf SPTE does not match the GFN of the struct kvm_mmu_page. A similar hole however remains if the modified PDE points to a non-leaf page. In this case the gfn can be made to match, but the role does not match: the original large 2MB page creates a kvm_mmu_page with direct=1, while the new 4KB needs a kvm_mmu_page with direct=0. However, kvm_mmu_get_child_sp() does not compare the role, and therefore reuses the page. The next step is installing a leaf (4KB) SPTE on the new path which records an rmap entry under the gfn resolved by the walk. But when that child is zapped its parent kvm_mmu_page has direct=1 and kvm_mmu_page_get_gfn() computes the gfn for the 4KB page as sp->gfn + index instead of using sp->shadowed_translation[] (or sp->gfns[] in older kernels). It therefore fails to remove the recorded entry. When the memslot is dropped the shadow page is freed but the rmap entry survives, as in the scenario that was already fixed. Code that later walks that gfn (dirty logging, MMU notifier invalidation, and so on) dereferences an sptep that lies in the freed page, causing the use-after-free.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-08 03:56 UTC

CWE

CWE-416 - Use After Free

Assigner

Linux mitre root

References

8 references

URL	Tags
https://git.kernel.org/stable/c/b1337aae5e194324e…
https://git.kernel.org/stable/c/9291654d69e08542d…
https://git.kernel.org/stable/c/2ad3afa40ac6aa340…
https://git.kernel.org/stable/c/5e470998a23e4c3d8…
https://git.kernel.org/stable/c/1ae7d5a6db6c190ce…
https://git.kernel.org/stable/c/81ccda30b4e83d8f5…
http://www.openwall.com/lists/oss-security/2026/07/06/7
https://github.com/V4bel/Januscape/blob/main/asse…	exploit

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < b1337aae5e194324e4810d561764e7793f8b3864 (git) Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < 9291654d69e08542de37755cebe4d5b02c3170d1 (git) Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < 2ad3afa40ac6aa340dada122f9abfa46c0a6eb35 (git) Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < 5e470998a23e4c3d89ed24e8172cb22747e61efa (git) Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < 1ae7d5a6db6c190ce183e3098ca0e0846e14d462 (git) Affected: 2032a93d66fa282ba0f2ea9152eeff9511fa9a96 , < 81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb (git)
Linux	Linux	Affected: 2.6.36 Unaffected: 0 , < 2.6.36 (semver) Unaffected: 6.1.177 , ≤ 6.1.* (semver) Unaffected: 6.6.144 , ≤ 6.6.* (semver) Unaffected: 6.12.95 , ≤ 6.12.* (semver) Unaffected: 6.18.38 , ≤ 6.18.* (semver) Unaffected: 7.1.3 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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JSON

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                {
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              "negate": false,
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        }
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Fix shadow paging use-after-free due to unexpected role\n\nCommit 0cb2af2ea66ad (\"KVM: x86: Fix shadow paging use-after-free due\nto unexpected GFN\") fixed a shadow paging mismatch between stored and\ncomputed GFNs; the bug could be triggered by changing a PDE mapping from\noutside the guest, and then deleting a memslot.  The rmap_remove()\ncall would miss entries created after the PDE change because the GFN\nof the leaf SPTE does not match the GFN of the struct kvm_mmu_page.\n\nA similar hole however remains if the modified PDE points to a non-leaf\npage.  In this case the gfn can be made to match, but the role does not\nmatch: the original large 2MB page creates a kvm_mmu_page with direct=1,\nwhile the new 4KB needs a kvm_mmu_page with direct=0.  However,\nkvm_mmu_get_child_sp() does not compare the role, and therefore reuses\nthe page.\n\nThe next step is installing a leaf (4KB) SPTE on the new path which\nrecords an rmap entry under the gfn resolved by the walk.  But when\nthat child is zapped its parent kvm_mmu_page has direct=1 and\nkvm_mmu_page_get_gfn() computes the gfn for the 4KB page as\nsp-\u003egfn + index instead of using sp-\u003eshadowed_translation[] (or sp-\u003egfns[]\nin older kernels).  It therefore fails to remove the recorded entry.\n\nWhen the memslot is dropped the shadow page is freed but the rmap\nentry survives, as in the scenario that was already fixed.  Code that\nlater walks that gfn (dirty logging, MMU notifier invalidation, and\nso on) dereferences an sptep that lies in the freed page, causing the\nuse-after-free."
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              "lang": "en",
              "value": "AV:L - The vulnerable code is reached through local KVM guest execution/KVM ioctls and shadow-MMU page fault handling, not by network packets or adjacent/physical input. In the highest reasonable scenario, an attacker runs code in a guest on an x86 KVM host with shadow paging/nested virtualization exposed.\nAC:L - The bug is a deterministic role-confusion/use-after-free in shadow page reuse, and the attacker can drive the guest mapping changes and later rmap walks needed to hit it. No condition outside attacker influence is required once the vulnerable KVM configuration is present.\nPR:L - The attacker needs the ability to run code in a KVM guest or otherwise access KVM VM execution interfaces, but does not need host root or administrative privileges. This is low privilege relative to the host security boundary.\nUI:N - No victim user action is required after the attacker-controlled guest or KVM workload is running. The trigger is caused by guest execution and KVM memory-management operations.\nS:C - This is a KVM guest-to-host escape class vulnerability, crossing from the guest security authority into the host kernel/hypervisor. Compromise can affect resources outside the guest\u2019s own scope.\nC:H - The stale rmap entry dereferences an SPTE pointer in freed shadow-page memory, creating a kernel use-after-free. Such memory corruption can be leveraged for host kernel information disclosure and arbitrary memory access.\nI:H - The use-after-free can corrupt host kernel shadow-MMU/rmap state and provides a plausible path to host kernel code execution or arbitrary modification. Public analysis treats this as a KVM escape class issue, so high integrity impact is defensible.\nA:H - At minimum, walking the stale rmap can dereference freed memory and crash or panic the host kernel. A malicious guest can repeatedly trigger the condition, causing high availability impact to the host and colocated guests."
            }
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          "url": "https://git.kernel.org/stable/c/9291654d69e08542de37755cebe4d5b02c3170d1"
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          "url": "https://git.kernel.org/stable/c/2ad3afa40ac6aa340dada122f9abfa46c0a6eb35"
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        {
          "url": "https://git.kernel.org/stable/c/81ccda30b4e83d8f5cc4fd50503c44e3a33abfeb"
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    "datePublished": "2026-07-04T11:51:49.052Z",
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CVE-2026-64531 (GCVE-0-2026-64531)

Vulnerability from cvelistv5 – Published: 2026-07-27 06:32 – Updated: 2026-08-22 04:12

Title

net: openvswitch: reject oversized nested action attrs

Summary

In the Linux kernel, the following vulnerability has been resolved: net: openvswitch: reject oversized nested action attrs Open vSwitch stores generated flow actions as nlattrs, whose nla_len field is u16. Commit a1e64addf3ff ("net: openvswitch: remove misbehaving actions length check") allowed the total sw_flow_actions stream to grow beyond 64 KiB, which is valid, but also removed the last guard preventing a generated nested action attribute from exceeding U16_MAX. An oversized generated container can thus be closed with a truncated nla_len. A later dump or teardown then walks a structurally different stream than the one that was validated. In particular, an oversized nested CLONE/CT action may cause subsequent bytes in the generated stream to be interpreted as independent actions. Keep the larger total-action-stream behavior, but make nested action close reject generated containers that do not fit in nla_len, and return the error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and CHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse construction order before discarding failed wrappers, so resources copied into the rejected tails are released before the wrappers are removed. Most failed outer wrappers are discarded by truncating actions_len after child resources have been released. CHECK_PKT_LEN also trims its parent after branch resources are gone. SET/TUNNEL close failures unwind their known tun_dst ownership directly, and SET_TO_MASKED has no external ownership and truncates on close failure.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

12 references

URL	Tags
https://git.kernel.org/stable/c/ab855641241387db0…
https://git.kernel.org/stable/c/c66bd2626c2764f23…
https://git.kernel.org/stable/c/d573250d228401f70…
https://git.kernel.org/stable/c/f1efff88584031913…
https://git.kernel.org/stable/c/dbd14f736be02cfe7…
https://git.kernel.org/stable/c/1b41cbe05b184f886…
https://git.kernel.org/stable/c/3f1f755366687d051…
http://www.openwall.com/lists/oss-security/2026/07/28/8
http://www.openwall.com/lists/oss-security/2026/0…
http://www.openwall.com/lists/oss-security/2026/08/01/1
http://www.openwall.com/lists/oss-security/2026/08/01/3
http://www.openwall.com/lists/oss-security/2026/08/22/1

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 057dbc5b72e9fcac439cd561c3a539b8a0edeb92 , < ab855641241387db062a5e41d9ad6b8561542572 (git) Affected: 2532adbfe917c0e71dba2650ffc6efe396314c87 , < c66bd2626c2764f23764ff0f8277f44a9cfe8349 (git) Affected: 4b1a0ee6164c7204c68ab5a9c48c07bfe8852485 , < d573250d228401f707f4dbc09d11227a6215ee5f (git) Affected: e6610f9c08b4c04cf7949c10fc246c071d00e935 , < f1efff8858403191361a01269c6fe8dd7f55a385 (git) Affected: a1e64addf3ff9257b45b78bc7d743781c3f41340 , < dbd14f736be02cfe73049bd801af89becd1a0749 (git) Affected: a1e64addf3ff9257b45b78bc7d743781c3f41340 , < 1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe (git) Affected: a1e64addf3ff9257b45b78bc7d743781c3f41340 , < 3f1f755366687d051174739fb99f7d560202f60b (git) Affected: 6b099d285d7ed324494b6d684f377aa103856118 (git) Affected: 5.15.180 , < 5.15.212 (semver) Affected: 6.1.132 , < 6.1.178 (semver) Affected: 6.6.84 , < 6.6.145 (semver) Affected: 6.12.20 , < 6.12.97 (semver) Affected: 6.13.8 , < 6.14 (semver)
Linux	Linux	Affected: 6.14 Unaffected: 0 , < 6.14 (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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JSON

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              "version": "a1e64addf3ff9257b45b78bc7d743781c3f41340",
              "versionType": "git"
            },
            {
              "lessThan": "3f1f755366687d051174739fb99f7d560202f60b",
              "status": "affected",
              "version": "a1e64addf3ff9257b45b78bc7d743781c3f41340",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "6b099d285d7ed324494b6d684f377aa103856118",
              "versionType": "git"
            },
            {
              "lessThan": "5.15.212",
              "status": "affected",
              "version": "5.15.180",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.132",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.84",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.97",
              "status": "affected",
              "version": "6.12.20",
              "versionType": "semver"
            },
            {
              "lessThan": "6.14",
              "status": "affected",
              "version": "6.13.8",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/openvswitch/flow_netlink.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.212",
                  "versionStartIncluding": "5.15.180",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.178",
                  "versionStartIncluding": "6.1.132",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "6.6.84",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.97",
                  "versionStartIncluding": "6.12.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.40",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.13.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: reject oversized nested action attrs\n\nOpen vSwitch stores generated flow actions as nlattrs, whose nla_len\nfield is u16. Commit a1e64addf3ff (\"net: openvswitch: remove\nmisbehaving actions length check\") allowed the total sw_flow_actions\nstream to grow beyond 64 KiB, which is valid, but also removed the last\nguard preventing a generated nested action attribute from exceeding\nU16_MAX.\n\nAn oversized generated container can thus be closed with a truncated\nnla_len. A later dump or teardown then walks a structurally different\nstream than the one that was validated. In particular, an oversized\nnested CLONE/CT action may cause subsequent bytes in the generated\nstream to be interpreted as independent actions.\n\nKeep the larger total-action-stream behavior, but make nested action\nclose reject generated containers that do not fit in nla_len, and return\nthe error through all callers. For recursive SAMPLE, CLONE, DEC_TTL, and\nCHECK_PKT_LEN builders, trim resource-owning action-list tails in reverse\nconstruction order before discarding failed wrappers, so resources copied\ninto the rejected tails are released before the wrappers are removed.\n\nMost failed outer wrappers are discarded by truncating actions_len after\nchild resources have been released. CHECK_PKT_LEN also trims its parent\nafter branch resources are gone. SET/TUNNEL close failures unwind their\nknown tun_dst ownership directly, and SET_TO_MASKED has no external\nownership and truncates on close failure."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable action builder is reached through local Generic Netlink requests such as OVS_FLOW_CMD_NEW or OVS_PACKET_CMD_EXECUTE. Remote packets cannot construct the malformed action stream.\nAC:L - The attacker deterministically controls the nested-action expansion, wrapped length, and resulting parser alignment; no race or uncontrollable condition is required.\nPR:L - The operations require CAP_NET_ADMIN but use GENL_UNS_ADMIN_PERM in namespace-aware families. An unprivileged user can obtain the required capability through an allowed user and network namespace.\nUI:N - Once the attacker sends the crafted netlink request, vulnerable dumping, teardown, or execution occurs without another user\u0027s participation.\nS:U - The vulnerability and its effects remain within the host kernel\u0027s security authority. Kernel privilege escalation from a user namespace does not constitute a CVSS scope change.\nC:H - Length truncation can reinterpret attacker-controlled userdata as an internal SET or CT action. The dump path can consequently dereference an attacker-selected kernel pointer and serialize referenced memory.\nI:H - Fake SET or CT actions can make execution or teardown perform reference-count operations, releases, and frees through attacker-controlled pointers. This provides exploitable memory-corruption primitives capable of kernel code execution.\nA:H - Attacker-controlled invalid pointers can cause a kernel oops or panic, while zero-length misparsed actions can cause a non-advancing execution loop and soft lockup."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T04:57:08.992Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ab855641241387db062a5e41d9ad6b8561542572"
        },
        {
          "url": "https://git.kernel.org/stable/c/c66bd2626c2764f23764ff0f8277f44a9cfe8349"
        },
        {
          "url": "https://git.kernel.org/stable/c/d573250d228401f707f4dbc09d11227a6215ee5f"
        },
        {
          "url": "https://git.kernel.org/stable/c/f1efff8858403191361a01269c6fe8dd7f55a385"
        },
        {
          "url": "https://git.kernel.org/stable/c/dbd14f736be02cfe73049bd801af89becd1a0749"
        },
        {
          "url": "https://git.kernel.org/stable/c/1b41cbe05b184f8861712f0806cc0c4f5d8c6dfe"
        },
        {
          "url": "https://git.kernel.org/stable/c/3f1f755366687d051174739fb99f7d560202f60b"
        }
      ],
      "title": "net: openvswitch: reject oversized nested action attrs",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64531",
    "datePublished": "2026-07-27T06:32:32.596Z",
    "dateReserved": "2026-07-19T15:36:31.794Z",
    "dateUpdated": "2026-08-22T04:12:18.141Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

Action not permitted

CERTFR-2026-AVI-1117

Solutions

CVE-2026-53359 (GCVE-0-2026-53359)

CVE-2026-64531 (GCVE-0-2026-64531)

Tags

Sightings

Nomenclature