CVE-2026-31515: af_key: validate families in pfkey_send_migrate()
Vulnerability summary
CVE-2026-31515 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.5% of scored vulnerabilities.
Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 32 · Related 30Timeline
- 22-04-2026PublishedVulnerability first disclosed.
- 15-10-2026Last modifiedVulnerability information updated.
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
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.13%
Chance of exploitation in the next 30 days
Percentile
3%
Versus all other CVEs
30-day change
Decrease -0.04 pp
From 0.17% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu157 products
- linuxAll versions (No fix recorded) | < 5.15.0-186.196 | < 6.8.0-136.136
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1112.119 | < 6.8.0-1061.64
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < d0c5aa8dd38887714f1aad04236a3620b56a5e4e | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < e06b596fc4eb01936a2e5dccad17c946d660bab8 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < 8ddf8de7e758f6888988467af9ffc8adf589fb16 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < d3225e6b9bd51ec177970a628fe4b11237ce87d5 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < 7b18692c59afb8e5c364c8e3ac01e51dd6b52028 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < 83f644ea92987c100b82d8481ae2230faeed3d34 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < ee836e820a40e2ca4da8af7310bff92d586772d4 | ≥ 08de61beab8a21c8e0b3906a97defda5f1f66ece, < eb2d16a7d599dc9d4df391b5e660df9949963786 | 2.6.21
- linux_kernel≥ 2.6.21.1, < 5.10.253 | ≥ 5.11, < 5.15.203 | ≥ 5.16, < 6.1.168 | ≥ 6.2, < 6.6.131 | ≥ 6.7, < 6.12.80 | ≥ 6.13, < 6.18.21 | ≥ 6.19, < 6.19.11 | 2.6.21 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7
Debian1 product
- linux< 6.1.170-1 | < 6.12.85-1 | < 6.19.11-1
3 vendors · 160 products
