5.5

CVE-2026-23403: linux

CVSS: 5.5v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-23403DEBIAN-CVE-2026-23403
Published 01-04-2026Last modified 11-05-2026
Open JSON

Vulnerability summary

CVE-2026-23403 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 6.8% 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
0.18%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 13 · Related 15
SUSE-SU-2026:21834-1SUSE-SU-2026:2195-1SUSE-SU-2026:2238-1USN-8098-10USN-8152-1USN-8163-1

Timeline

  1. 01-04-2026
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: apparmor: fix memory leak in verify_header The function sets `*ns = NULL` on every call, leaking the namespace string allocated in previous iterations when multiple profiles are unpacked. This also breaks namespace consistency checking since *ns is always NULL when the comparison is made. Remove the incorrect assignment. The caller (aa_unpack) initializes *ns to NULL once before the loop, which is sufficient.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

7%

Versus all other CVEs

30-day change

0.00 pp

From 0.18% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.18%

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

Affected systems

Ubuntu156 products
  • linuxAll versions (No fix recorded) | < 4.15.0-249.261 | < 5.4.0-227.247 | < 5.15.0-173.183 | < 6.8.0-106.106 | < 6.17.0-19.19
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 4.15.0-1191.204 | < 5.4.0-1156.166 | < 5.15.0-1103.110 | < 6.8.0-1050.53 | < 6.17.0-1009.9
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 9d678eb0fe55c9195d9a253e8c5b82a87b930737 | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 6b79abcb3c985e153fcf9d395e1d4336081aabc2 | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < bcf82c0c5a8b383fd2d5d8f3fd880cdcab2ac557 | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 663ce34786e759ebcbeb3060685c20bcc886d51a | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 786e2c2a87d9c505f33321d1fd23a176aa8ddeb1 | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 4f0889f2df1ab99224a5e1ac4e20437eea5fe38e | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < 42fd831abfc15d0643c14688f0522556b347e7e6 | ≥ dd51c84857630e77c139afe4d9bba65fc051dc3f, < e38c55d9f834e5b848bfed0f5c586aaf45acb825 | 3.12
  • linux_kernel≥ 3.12.1, < 5.10.253 | ≥ 5.11, < 5.15.203 | ≥ 5.16, < 6.1.169 | ≥ 6.2, < 6.6.130 | ≥ 6.7, < 6.12.77 | ≥ 6.13, < 6.18.18 | ≥ 6.19, < 6.19.8 | 3.12 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7
Debian1 product
  • linux< 6.1.164-1 | < 6.12.74-2 | < 6.19.6-2

3 vendors · 159 products

References

28 links
Show all 28 references