Vulnerability-Lookup

GHSA-PVJ3-F5V8-HGXH

Vulnerability from github – Published: 2025-02-27 03:34 – Updated: 2025-02-27 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

ipv6: mcast: extend RCU protection in igmp6_send()

igmp6_send() can be called without RTNL or RCU being held.

Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF.

Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.

Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2025-21759"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-27T03:15:16Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: mcast: extend RCU protection in igmp6_send()\n\nigmp6_send() can be called without RTNL or RCU being held.\n\nExtend RCU protection so that we can safely fetch the net pointer\nand avoid a potential UAF.\n\nNote that we no longer can use sock_alloc_send_skb() because\nipv6.igmp_sk uses GFP_KERNEL allocations which can sleep.\n\nInstead use alloc_skb() and charge the net-\u003eipv6.igmp_sk\nsocket under RCU protection.",
  "id": "GHSA-pvj3-f5v8-hgxh",
  "modified": "2025-02-27T18:31:10Z",
  "published": "2025-02-27T03:34:05Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21759"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/087c1faa594fa07a66933d750c0b2610aa1a2946"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2025-21759 (GCVE-0-2025-21759)

Vulnerability from cvelistv5 – Published: 2025-02-27 02:18 – Updated: 2026-08-05 11:54

Title

ipv6: mcast: extend RCU protection in igmp6_send()

Summary

In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.

Severity

7.8 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2025-02-27 17:57 UTC

CWE

CWE-416 - Use After Free

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/81b25a07ebf53f9ef…
https://git.kernel.org/stable/c/0bf8e2f3768629d43…
https://git.kernel.org/stable/c/8e92d6a413feaf968…
https://git.kernel.org/stable/c/087c1faa594fa07a6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 , < 81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a (git) Affected: b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 , < 0bf8e2f3768629d437a32cb824149e6e98254381 (git) Affected: b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 , < 8e92d6a413feaf968a33f0b439ecf27404407458 (git) Affected: b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 , < 087c1faa594fa07a66933d750c0b2610aa1a2946 (git)
Linux	Linux	Affected: 2.6.26 Unaffected: 0 , < 2.6.26 (semver) Unaffected: 6.6.79 , ≤ 6.6.* (semver) Unaffected: 6.12.16 , ≤ 6.12.* (semver) Unaffected: 6.13.4 , ≤ 6.13.* (semver) Unaffected: 6.14 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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              "content": {
                "id": "CVE-2025-21759",
                "options": [
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                  }
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                "role": "CISA Coordinator",
                "timestamp": "2025-02-27T17:57:46.460072Z",
                "version": "2.0.3"
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                {
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        }
      ],
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          "scenarios": [
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              "value": "AV:L - Although igmp6_send() can be scheduled by adjacent MLD Query packets, the freeing side of the race requires network-namespace dismantle or a netdev netns move, which is driven by local syscalls (unshare/setns, RTM_NEWLINK with IFLA_NET_NS_FD, process exit). A local unprivileged user controls both sides of the race entirely, making local access the reliable exploitation vector.\nAC:L - The attacker drives both halves: they schedule igmp6_send() at will (multicast join/leave, link up/down, or timed MLD reports) and trigger the free by destroying their own netns or moving the device out of it, and can retry the race indefinitely while heap-grooming the freed struct net/struct sock.\nPR:L - Only an unprivileged local account is needed \u2014 the CAP_NET_ADMIN checks on the netns-move path are ns_capable() against the target netns user_ns, which is satisfied inside a user namespace created with unshare -Urn, and IPv6 multicast joins require no privilege at all.\nUI:N - The entire sequence \u2014 namespace setup, multicast group joins, and namespace teardown \u2014 is performed by the attacker\u0027s own processes with no action from any other user.\nS:U - The corrupted objects (struct net, struct sock) and the resulting code execution are all within the kernel\u0027s own security authority; no hypervisor, IOMMU, or other security boundary is crossed.\nC:H - The use-after-free reads sk-\u003esk_sndbuf, sk-\u003esk_allocation, sk-\u003esk_socket, net-\u003emib pointers and net-\u003enf.hooks_ipv6[] from freed-and-reallocated memory, giving an attacker who sprays the freed slab a controllable pointer-dereference primitive that can be turned into arbitrary kernel memory disclosure.\nI:H - skb_set_owner_w() performs refcount_add() into the freed socket and NF_HOOK() calls a function pointer fetched from the freed struct net\u0027s netfilter hook array, yielding both a write primitive and control-flow hijack suitable for full privilege escalation.\nA:H - Dereferencing a freed struct net and its igmp_sk reliably produces a kernel oops/panic (slab-use-after-free, invalid pointer dereference in the netfilter or socket accounting path), and the race can be repeated to crash the machine."
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    "datePublished": "2025-02-27T02:18:12.994Z",
    "dateReserved": "2024-12-29T08:45:45.761Z",
    "dateUpdated": "2026-08-05T11:54:12.048Z",
    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
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}

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

Related by attack behaviour

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