CVE-2026-63924 (GCVE-0-2026-63924)

Vulnerability from cvelistv5 – Published: 2026-07-19 14:55 – Updated: 2026-08-05 12:37
VLAI
Title
ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()
Summary
In the Linux kernel, the following vulnerability has been resolved: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo() ipv6_hop_jumbo() calls pskb_trim_rcsum(), which can change skb pointers. Let's recompute nh pointer to make sure any change won't mess things up.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b3ac54e5c905f86d22b502eacb5686a282c5659f (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 645b99b1a185c91a79bdac4c5de0f91b212d64f0 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 9e883eaa878f4337b5873c706efb5a192364ed18 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < bddaa4dfc7f36e1ee343a0622f69288af2b9ace9 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 72af7beae774e46ed543f3f2f267bf0a141bfcdd (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c512e1c819dfbf6ae95ee7a44b65b9ad98979157 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 2b56bbd928c030894c270cd33d60286326919458 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < d47548a36639095939f4747d4c43f2271366f565 (git)
guessed Create a notification for this product.
Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 5.10.259 , ≤ 5.10.* (semver)
Unaffected: 5.15.210 , ≤ 5.15.* (semver)
Unaffected: 6.1.176 , ≤ 6.1.* (semver)
Unaffected: 6.6.143 , ≤ 6.6.* (semver)
Unaffected: 6.12.93 , ≤ 6.12.* (semver)
Unaffected: 6.18.35 , ≤ 6.18.* (semver)
Unaffected: 7.0.12 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
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          "programFiles": [
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              "version": "7.1",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
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        }
      ],
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            "version": "3.1"
          },
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              "value": "AV:N - The bug is in the IPv6 input path (ipv6_rcv \u2192 ip6_rcv_core \u2192 ipv6_parse_hopopts) triggered by a crafted IPv6 packet with hop-by-hop options containing a Jumbo Payload TLV, reachable from any remote peer that can deliver IPv6 to the host.\nAC:L - An attacker fully controls the crafted IPv6 packet (HBH layout, jumbo length, trailing TLVs) and can send it repeatedly; once the skb is cloned/shared during receive and pskb_trim_rcsum reallocates the head, the stale-pointer UAF is deterministically triggered without races or victim-specific state.\nPR:N - No authentication or local privileges are required; any unauthenticated remote host that can send IPv6 traffic to a listening interface reaches the vulnerable receive handler with no capability or namespace checks along the path.\nUI:N - Exploitation requires only delivery of a malicious IPv6 packet and does not depend on any victim user action such as opening files, clicking links, or mounting filesystems.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security domain; it does not cross a VM, container, or IOMMU boundary by itself.\nC:H - Continued HBH TLV parsing through the stale nh pointer is a use-after-free read of freed skb head memory, which per kernel guidance enables arbitrary kernel memory disclosure when the freed slab is reused.\nI:H - Stale-pointer UAF during TLV length/type parsing can yield unbounded out-of-bounds reads and corrupt subsequent parsing state, providing memory corruption primitives that can be developed into arbitrary kernel writes or code execution.\nA:H - Dereferencing the freed network-header pointer during TLV parsing can cause immediate kernel oops/panic from invalid memory access, and UAF-triggered parsing errors reliably drop or crash the receive path."
            }
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        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        {
          "url": "https://git.kernel.org/stable/c/d47548a36639095939f4747d4c43f2271366f565"
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      "title": "ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()",
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    "cveId": "CVE-2026-63924",
    "datePublished": "2026-07-19T14:55:25.702Z",
    "dateReserved": "2026-07-19T07:54:57.021Z",
    "dateUpdated": "2026-08-05T12:37:19.118Z",
    "state": "PUBLISHED"
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      "date": "2026-09-21",
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      "percentile": "0.51807"
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            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()\n\nipv6_hop_jumbo() calls pskb_trim_rcsum(), which can change skb pointers.\nLet\u0027s recompute nh pointer to make sure any change won\u0027t mess things up."
          }
        ],
        "id": "CVE-2026-63924",
        "lastModified": "2026-07-27T17:44:23.777",
        "metrics": {
          "cvssMetricV31": [
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              "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",
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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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            "url": "https://git.kernel.org/stable/c/d47548a36639095939f4747d4c43f2271366f565"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Awaiting Analysis"
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Important",
      "current_release_date": "2026-07-22T03:09:28+00:00",
      "cve": "CVE-2026-63924",
      "id": "CVE-2026-63924",
      "initial_release_date": "2026-07-19T00:00:00+00:00",
      "product_status:known_affected": "260",
      "product_status:under_investigation": "14",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ipv6: exthdrs: refresh nh pointer after ipv6_hop_jumbo()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63924.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "important",
      "current_release_date": "2026-09-10T02:30:10Z",
      "cve": "CVE-2026-63924",
      "id": "CVE-2026-63924",
      "initial_release_date": "2026-07-21T13:03:27Z",
      "product_status:known_affected": "46",
      "product_status:known_not_affected": "97",
      "product_status:recommended": "335",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-63924",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-63924.json",
      "version": "13"
    }
  }
}



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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.


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.