CVE-2026-45886 (GCVE-0-2026-45886)

Vulnerability from cvelistv5 – Published: 2026-05-27 12:16 – Updated: 2026-05-27 12:16
VLAI
Title
bpf: Fix bpf_xdp_store_bytes proto for read-only arg
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bpf_xdp_store_bytes proto for read-only arg While making some maps in Cilium read-only from the BPF side, we noticed that the bpf_xdp_store_bytes proto is incorrect. In particular, the verifier was throwing the following error: ; ret = ctx_store_bytes(ctx, l3_off + offsetof(struct iphdr, saddr), &nat->address, 4, 0); 635: (79) r1 = *(u64 *)(r10 -144) ; R1=ctx() R10=fp0 fp-144=ctx() 636: (b4) w2 = 26 ; R2=26 637: (b4) w4 = 4 ; R4=4 638: (b4) w5 = 0 ; R5=0 639: (85) call bpf_xdp_store_bytes#190 write into map forbidden, value_size=6 off=0 size=4 nat comes from a BPF_F_RDONLY_PROG map, so R3 is a PTR_TO_MAP_VALUE. The verifier checks the helper's memory access to R3 in check_mem_size_reg, as it reaches ARG_CONST_SIZE argument. The third argument has expected type ARG_PTR_TO_UNINIT_MEM, which includes the MEM_WRITE flag. The verifier thus checks for a BPF_WRITE access on R3. Given R3 points to a read-only map, the check fails. Conversely, ARG_PTR_TO_UNINIT_MEM can also lead to the helper reading from uninitialized memory. This patch simply fixes the expected argument type to match that of bpf_skb_store_bytes.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e (git)
Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < ddc34a1b85505c919026ddc82fafdada9a160b15 (git)
Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < 0db169a91381a473b7974021d1c02f8da72c5775 (git)
Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < d7b87adeb0eb539b9b824b101bb14fb01e41240b (git)
Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < 57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52 (git)
Affected: 3f364222d032eea6b245780e845ad213dab28cdd , < 6557f1565d779851c4db9c488c49c05a47a6e72f (git)
Create a notification for this product.
Linux Linux Affected: 5.18
Unaffected: 0 , < 5.18 (semver)
Unaffected: 6.1.165 , ≤ 6.1.* (semver)
Unaffected: 6.6.128 , ≤ 6.6.* (semver)
Unaffected: 6.12.75 , ≤ 6.12.* (semver)
Unaffected: 6.18.14 , ≤ 6.18.* (semver)
Unaffected: 6.19.4 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/core/filter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            },
            {
              "lessThan": "ddc34a1b85505c919026ddc82fafdada9a160b15",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            },
            {
              "lessThan": "0db169a91381a473b7974021d1c02f8da72c5775",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            },
            {
              "lessThan": "d7b87adeb0eb539b9b824b101bb14fb01e41240b",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            },
            {
              "lessThan": "57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            },
            {
              "lessThan": "6557f1565d779851c4db9c488c49c05a47a6e72f",
              "status": "affected",
              "version": "3f364222d032eea6b245780e845ad213dab28cdd",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/core/filter.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.18"
            },
            {
              "lessThan": "5.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.128",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.165",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.128",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.75",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.14",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.4",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "versionStartIncluding": "5.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix bpf_xdp_store_bytes proto for read-only arg\n\nWhile making some maps in Cilium read-only from the BPF side, we noticed\nthat the bpf_xdp_store_bytes proto is incorrect. In particular, the\nverifier was throwing the following error:\n\n  ; ret = ctx_store_bytes(ctx, l3_off + offsetof(struct iphdr, saddr),\n                          \u0026nat-\u003eaddress, 4, 0);\n  635: (79) r1 = *(u64 *)(r10 -144)     ; R1=ctx() R10=fp0 fp-144=ctx()\n  636: (b4) w2 = 26                     ; R2=26\n  637: (b4) w4 = 4                      ; R4=4\n  638: (b4) w5 = 0                      ; R5=0\n  639: (85) call bpf_xdp_store_bytes#190\n  write into map forbidden, value_size=6 off=0 size=4\n\nnat comes from a BPF_F_RDONLY_PROG map, so R3 is a PTR_TO_MAP_VALUE.\nThe verifier checks the helper\u0027s memory access to R3 in\ncheck_mem_size_reg, as it reaches ARG_CONST_SIZE argument. The third\nargument has expected type ARG_PTR_TO_UNINIT_MEM, which includes the\nMEM_WRITE flag. The verifier thus checks for a BPF_WRITE access on R3.\nGiven R3 points to a read-only map, the check fails.\n\nConversely, ARG_PTR_TO_UNINIT_MEM can also lead to the helper reading\nfrom uninitialized memory.\n\nThis patch simply fixes the expected argument type to match that of\nbpf_skb_store_bytes."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-27T12:16:58.000Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e"
        },
        {
          "url": "https://git.kernel.org/stable/c/ddc34a1b85505c919026ddc82fafdada9a160b15"
        },
        {
          "url": "https://git.kernel.org/stable/c/0db169a91381a473b7974021d1c02f8da72c5775"
        },
        {
          "url": "https://git.kernel.org/stable/c/d7b87adeb0eb539b9b824b101bb14fb01e41240b"
        },
        {
          "url": "https://git.kernel.org/stable/c/57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52"
        },
        {
          "url": "https://git.kernel.org/stable/c/6557f1565d779851c4db9c488c49c05a47a6e72f"
        }
      ],
      "title": "bpf: Fix bpf_xdp_store_bytes proto for read-only arg",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-45886",
    "datePublished": "2026-05-27T12:16:58.000Z",
    "dateReserved": "2026-05-13T15:03:33.082Z",
    "dateUpdated": "2026-05-27T12:16:58.000Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-45886",
      "date": "2026-05-29",
      "epss": "0.00024",
      "percentile": "0.07393"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-45886\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-27T14:17:02.567\",\"lastModified\":\"2026-05-27T14:48:31.480\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbpf: Fix bpf_xdp_store_bytes proto for read-only arg\\n\\nWhile making some maps in Cilium read-only from the BPF side, we noticed\\nthat the bpf_xdp_store_bytes proto is incorrect. In particular, the\\nverifier was throwing the following error:\\n\\n  ; ret = ctx_store_bytes(ctx, l3_off + offsetof(struct iphdr, saddr),\\n                          \u0026nat-\u003eaddress, 4, 0);\\n  635: (79) r1 = *(u64 *)(r10 -144)     ; R1=ctx() R10=fp0 fp-144=ctx()\\n  636: (b4) w2 = 26                     ; R2=26\\n  637: (b4) w4 = 4                      ; R4=4\\n  638: (b4) w5 = 0                      ; R5=0\\n  639: (85) call bpf_xdp_store_bytes#190\\n  write into map forbidden, value_size=6 off=0 size=4\\n\\nnat comes from a BPF_F_RDONLY_PROG map, so R3 is a PTR_TO_MAP_VALUE.\\nThe verifier checks the helper\u0027s memory access to R3 in\\ncheck_mem_size_reg, as it reaches ARG_CONST_SIZE argument. The third\\nargument has expected type ARG_PTR_TO_UNINIT_MEM, which includes the\\nMEM_WRITE flag. The verifier thus checks for a BPF_WRITE access on R3.\\nGiven R3 points to a read-only map, the check fails.\\n\\nConversely, ARG_PTR_TO_UNINIT_MEM can also lead to the helper reading\\nfrom uninitialized memory.\\n\\nThis patch simply fixes the expected argument type to match that of\\nbpf_skb_store_bytes.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0db169a91381a473b7974021d1c02f8da72c5775\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6557f1565d779851c4db9c488c49c05a47a6e72f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/d7b87adeb0eb539b9b824b101bb14fb01e41240b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ddc34a1b85505c919026ddc82fafdada9a160b15\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.