# CVE-2026-31515: af_key: validate families in pfkey_send_migrate()

Status: published. Published: 2026-04-22. Updated: 2026-11-05.

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

af_key: validate families in pfkey_send_migrate()

syzbot was able to trigger a crash in skb_put() [1]

Issue is that pfkey_send_migrate() does not check old/new families,
and that set_ipsecrequest() @family argument was truncated,
thus possibly overfilling the skb.

Validate families early, do not wait set_ipsecrequest().

[1]

skbuff: skb_over_panic: text:ffffffff8a752120 len:392 put:16 head:ffff88802a4ad040 data:ffff88802a4ad040 tail:0x188 end:0x180 dev:<NULL>
 kernel BUG at net/core/skbuff.c:214 !
Call Trace:
 <TASK>
  skb_over_panic net/core/skbuff.c:219 [inline]
  skb_put+0x159/0x210 net/core/skbuff.c:2655
  skb_put_zero include/linux/skbuff.h:2788 [inline]
  set_ipsecrequest net/key/af_key.c:3532 [inline]
  pfkey_send_migrate+0x1270/0x2e50 net/key/af_key.c:3636
  km_migrate+0x155/0x260 net/xfrm/xfrm_state.c:2848
  xfrm_migrate+0x2140/0x2450 net/xfrm/xfrm_policy.c:4705
  xfrm_do_migrate+0x8ff/0xaa0 net/xfrm/xfrm_user.c:3150

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < d0c5aa8dd38887714f1aad04236a3620b56a5e4e (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < e06b596fc4eb01936a2e5dccad17c946d660bab8 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < 8ddf8de7e758f6888988467af9ffc8adf589fb16 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < d3225e6b9bd51ec177970a628fe4b11237ce87d5 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < 7b18692c59afb8e5c364c8e3ac01e51dd6b52028 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < 83f644ea92987c100b82d8481ae2230faeed3d34 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < ee836e820a40e2ca4da8af7310bff92d586772d4 (affected, git); ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece; < eb2d16a7d599dc9d4df391b5e660df9949963786 (affected, git). Source: CNA: Linux
- Linux / Linux: 2.6.21 (affected); ≥ 0; < 2.6.21 (unaffected, semver); ≥ 5.10.253; ≤ 5.10.* (unaffected, semver); ≥ 5.15.203; ≤ 5.15.* (unaffected, semver); ≥ 6.1.168; ≤ 6.1.* (unaffected, semver); ≥ 6.6.131; ≤ 6.6.* (unaffected, semver); ≥ 6.12.80; ≤ 6.12.* (unaffected, semver); ≥ 6.18.21; ≤ 6.18.* (unaffected, semver); ≥ 6.19.11; ≤ 6.19.* (unaffected, semver); ≥ 7.0; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.5; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP: ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-05; percentile 2.54%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/d0c5aa8dd38887714f1aad04236a3620b56a5e4e (CNA: Linux)

- https://git.kernel.org/stable/c/e06b596fc4eb01936a2e5dccad17c946d660bab8 (CNA: Linux)

- https://git.kernel.org/stable/c/8ddf8de7e758f6888988467af9ffc8adf589fb16 (CNA: Linux)

- https://git.kernel.org/stable/c/d3225e6b9bd51ec177970a628fe4b11237ce87d5 (CNA: Linux)

- https://git.kernel.org/stable/c/7b18692c59afb8e5c364c8e3ac01e51dd6b52028 (CNA: Linux)

- https://git.kernel.org/stable/c/83f644ea92987c100b82d8481ae2230faeed3d34 (CNA: Linux)

- https://git.kernel.org/stable/c/ee836e820a40e2ca4da8af7310bff92d586772d4 (CNA: Linux)

- https://git.kernel.org/stable/c/eb2d16a7d599dc9d4df391b5e660df9949963786 (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-082556.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-31515; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-31515; retrieved 2026-11-05; source updated Not reported

Revision: bc6d5659e9361ef5bdf53373667dea470767e26abdc36ca2656c854dd5833e70

Canonical: https://y2.dev/cve/CVE-2026-31515

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.