5.5

CVE-2026-31495: linux

CVSS: 5.5v3.1MediumModified
AliasesUBUNTU-CVE-2026-31495DEBIAN-CVE-2026-31495
Published 22-04-2026Last modified 15-10-2026
Open JSON

Vulnerability summary

CVE-2026-31495 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 6.1% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.17%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 40 · Related 38
MGASA-2026-0108MGASA-2026-0110OPENSUSE-SU-2026:21388-1SUSE-SU-2026:22433-1SUSE-SU-2026:22436-1SUSE-SU-2026:22458-1

Timeline

  1. 22-04-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: use netlink policy range checks Replace manual range and mask validations with netlink policy annotations in ctnetlink code paths, so that the netlink core rejects invalid values early and can generate extack errors. - CTA_PROTOINFO_TCP_STATE: reject values > TCP_CONNTRACK_SYN_SENT2 at policy level, removing the manual >= TCP_CONNTRACK_MAX check. - CTA_PROTOINFO_TCP_WSCALE_ORIGINAL/REPLY: reject values > TCP_MAX_WSCALE (14). The normal TCP option parsing path already clamps to this value, but the ctnetlink path accepted 0-255, causing undefined behavior when used as a u32 shift count. - CTA_FILTER_ORIG_FLAGS/REPLY_FLAGS: use NLA_POLICY_MASK with CTA_FILTER_F_ALL, removing the manual mask checks. - CTA_EXPECT_FLAGS: use NLA_POLICY_MASK with NF_CT_EXPECT_MASK, adding a new mask define grouping all valid expect flags. Extracted from a broader nf-next patch by Florian Westphal, scoped to ctnetlink for the fixes tree.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.17%

Chance of exploitation in the next 30 days

Percentile

6%

Versus all other CVEs

30-day change

+0.04 pp

From 0.13% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.17%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

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≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 435b576cd2faa75154777868f8cbb73bf71644d3 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 2ef71307c86a9f866d6e28f1a0c06e2e9d794474 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 4f7d25f3f0786402ba48ff7d13b6241d77d975f5 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < fcec5ce2d73a41668b24e3f18c803541602a59f6 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 675c913b940488a84effdeeac5a1cfb657b59804 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < c6cb41eaae875501eaaa487b8db6539feb092292 | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 45c33e79ae705b7af97e3117672b6cd258dd0b1b | ≥ c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4, < 8f15b5071b4548b0aafc03b366eb45c9c6566704 | 2.6.22
  • linux_kernel≥ 2.6.22.1, < 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 | 2.6.22 | 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

References

43 links
Show all 43 references