Vulnerability-Lookup

FKIE_CVE-2026-64439

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-10-24 13:10

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion. KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name: BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7 The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site. Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad	Patch

Impacted products

	Vendor	Product	Version
	linux	linux_kernel	*
	linux	linux_kernel	*

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "crypto/krb5/krb5_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ef6feb77e2d91761427c5b773edc9c97e1b706ad",
              "status": "affected",
              "version": "00244da40f7821b242c4612428d4192230dba27f",
              "versionType": "git"
            },
            {
              "lessThan": "2b7bd6dccff14b8b632c5244f1fd506918077221",
              "status": "affected",
              "version": "00244da40f7821b242c4612428d4192230dba27f",
              "versionType": "git"
            },
            {
              "lessThan": "6c9dddeb582fde005360f4fe02c760d45ca05fb5",
              "status": "affected",
              "version": "00244da40f7821b242c4612428d4192230dba27f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "crypto/krb5/krb5_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "1DA3E752-10DF-4260-A04E-FB6A07086768",
              "versionEndExcluding": "6.18.39",
              "versionStartIncluding": "6.15",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "6228DDD6-4557-4AA3-9F43-AB995D471E42",
              "versionEndExcluding": "7.1.4",
              "versionStartIncluding": "6.19",
              "vulnerable": true
            }
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          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: krb5 - filter out async aead implementations at alloc\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and\nrfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL\ncompletion callback and treat any negative return from\ncrypto_aead_{encrypt,decrypt}() as terminal, falling through to\nkfree_sensitive(buffer).  When the encrypt_name resolves to an\nasync AEAD instance the request returns -EINPROGRESS, the buffer\nis freed while the backend\u0027s worker still holds a pointer, and the\nworker dereferences the freed slab on completion.\n\nKASAN report under UML+SLUB with a synthetic async aead backend\nbound to krb5-\u003eencrypt_name:\n\n  BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7\n\nThe helpers were written synchronously, so filter the async\ninstances out at allocation time instead of plumbing\ncrypto_wait_req() through every call site.\n\nReachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and\nnet/ceph/crypto.c on systems with an async AEAD provider bound to\nthe krb5 enctype name."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\ncrypto: krb5 - filtrar implementaciones AEAD as\u00edncronas en la asignaci\u00f3n\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() en rfc3961_simplified.c y rfc8009_encrypt(), rfc8009_decrypt() en rfc8009_aes2.c establecen una devoluci\u00f3n de llamada de finalizaci\u00f3n NULL y tratan cualquier retorno negativo de crypto_aead_{encrypt,decrypt}() como terminal, pasando a kfree_sensitive(buffer). Cuando el encrypt_name se resuelve en una instancia AEAD as\u00edncrona, la solicitud devuelve -EINPROGRESS, el b\u00fafer es liberado mientras el trabajador del backend a\u00fan mantiene un puntero, y el trabajador desreferencia el slab liberado al finalizar.\n\nInforme KASAN bajo UML+SLUB con un backend AEAD as\u00edncrono sint\u00e9tico vinculado a krb5  -\u003e  encrypt_name:\n\nBUG: KASAN: uso despu\u00e9s de liberaci\u00f3n de slab en t5_stub_complete+0x7d/0xc7\n\nLos ayudantes fueron escritos de forma s\u00edncrona, as\u00ed que filtrar las instancias as\u00edncronas en el momento de la asignaci\u00f3n en lugar de pasar crypto_wait_req() a trav\u00e9s de cada sitio de llamada.\n\nAlcanzable a trav\u00e9s de net/rxrpc/rxgk.c, fs/afs/cm_security.c y net/ceph/crypto.c en sistemas con un proveedor AEAD as\u00edncrono vinculado al nombre de tipo de cifrado krb5."
    }
  ],
  "id": "CVE-2026-64439",
  "lastModified": "2026-10-24T13:10:00.147",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-07-25T10:17:28.447",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "tags": [
        "Patch"
      ],
      "url": "https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5"
    },
    {
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        "Patch"
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      "url": "https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-416"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2026-64439 (GCVE-0-2026-64439)

Vulnerability from cvelistv5 – Published: 2026-07-25 08:51 – Updated: 2026-08-17 04:55

Title

crypto: krb5 - filter out async aead implementations at alloc

Summary

Severity

9.8 (Critical)


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

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6641 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/ef6feb77e2d917614…
https://git.kernel.org/stable/c/2b7bd6dccff14b8b6…
https://git.kernel.org/stable/c/6c9dddeb582fde005…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 00244da40f7821b242c4612428d4192230dba27f , < ef6feb77e2d91761427c5b773edc9c97e1b706ad (git) Affected: 00244da40f7821b242c4612428d4192230dba27f , < 2b7bd6dccff14b8b632c5244f1fd506918077221 (git) Affected: 00244da40f7821b242c4612428d4192230dba27f , < 6c9dddeb582fde005360f4fe02c760d45ca05fb5 (git)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "crypto/krb5/krb5_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ef6feb77e2d91761427c5b773edc9c97e1b706ad",
              "status": "affected",
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              "versionType": "git"
            },
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              "lessThan": "2b7bd6dccff14b8b632c5244f1fd506918077221",
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              "version": "00244da40f7821b242c4612428d4192230dba27f",
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            },
            {
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              "status": "affected",
              "version": "00244da40f7821b242c4612428d4192230dba27f",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "crypto/krb5/krb5_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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                  "vulnerable": true
                },
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                  "vulnerable": true
                },
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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      "descriptions": [
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: krb5 - filter out async aead implementations at alloc\n\nkrb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and\nrfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL\ncompletion callback and treat any negative return from\ncrypto_aead_{encrypt,decrypt}() as terminal, falling through to\nkfree_sensitive(buffer).  When the encrypt_name resolves to an\nasync AEAD instance the request returns -EINPROGRESS, the buffer\nis freed while the backend\u0027s worker still holds a pointer, and the\nworker dereferences the freed slab on completion.\n\nKASAN report under UML+SLUB with a synthetic async aead backend\nbound to krb5-\u003eencrypt_name:\n\n  BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7\n\nThe helpers were written synchronously, so filter the async\ninstances out at allocation time instead of plumbing\ncrypto_wait_req() through every call site.\n\nReachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and\nnet/ceph/crypto.c on systems with an async AEAD provider bound to\nthe krb5 enctype name."
        }
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            "baseSeverity": "CRITICAL",
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          },
          "scenarios": [
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              "lang": "en",
              "value": "AV:N - An unauthenticated remote peer can reach the vulnerable Kerberos decrypt helper through the UDP RxRPC/RxGK RESPONSE path; Ceph and AFS also expose network-driven paths.\nAC:L - Once an async AEAD implementation is selected, each accepted operation can return -EINPROGRESS and trigger the UAF. The attacker controls and can repeatedly invoke the packet flow, enabling heap grooming and race amplification.\nPR:N - RxGK decrypts the attacker-supplied token before validating the ticket, nonce, or authenticator. Looking up an installed server key selects the cipher but does not authenticate the peer.\nUI:N - A listening service processes the challenge and malicious response automatically without any victim action.\nS:U - Exploitation compromises resources governed by the same host kernel security authority and does not inherently cross a VM, IOMMU, or equivalent boundary.\nC:H - The freed request contains transform, callback, context, IV, and scatterlist-related state that can be reclaimed or accessed asynchronously, supporting controlled kernel-memory disclosure.\nI:H - The backend can write through stale scatterlist pointers, while reclaimed callback and request fields can enable arbitrary memory corruption or control-flow hijacking.\nA:H - The async worker dereferences freed or zeroed request state, allowing a repeatable kernel oops or panic; the defect has also been directly observed as a KASAN slab use-after-free."
            }
          ]
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        "dateUpdated": "2026-08-17T04:55:40.947Z",
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        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5"
        }
      ],
      "title": "crypto: krb5 - filter out async aead implementations at alloc",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64439",
    "datePublished": "2026-07-25T08:51:12.422Z",
    "dateReserved": "2026-07-19T15:36:31.788Z",
    "dateUpdated": "2026-08-17T04:55:40.947Z",
    "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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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