5.5

CVE-2026-43107: linux Incorrect Calculation of Buffer Size

CVSS: 5.5v3.1MediumModified
AliasesUBUNTU-CVE-2026-43107DEBIAN-CVE-2026-43107CGA-4mxc-38m5-g6fj
Published 06-05-2026Last modified 21-10-2026
Open JSON

Vulnerability summary

CVE-2026-43107 is a medium (CVSS 5.5) Incorrect Calculation of Buffer Size vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5% 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
0.16%
0%100%
Low · +0.05 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 25 · Related 26
OPENSUSE-SU-2026:21388-1SUSE-SU-2026:22521-1SUSE-SU-2026:22522-1SUSE-SU-2026:22665-1SUSE-SU-2026:22666-1SUSE-SU-2026:22742-1

Timeline

  1. 06-05-2026
    PublishedVulnerability first disclosed.
  2. 21-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: account XFRMA_IF_ID in aevent size calculation xfrm_get_ae() allocates the reply skb with xfrm_aevent_msgsize(), then build_aevent() appends attributes including XFRMA_IF_ID when x->if_id is set. xfrm_aevent_msgsize() does not include space for XFRMA_IF_ID. For states with if_id, build_aevent() can fail with -EMSGSIZE and hit BUG_ON(err < 0) in xfrm_get_ae(), turning a malformed netlink interaction into a kernel panic. Account XFRMA_IF_ID in the size calculation unconditionally and replace the BUG_ON with normal error unwinding.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

+0.05 pp

From 0.11% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.16%

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

Ubuntu153 products
  • linuxAll versions (No fix recorded) | < 6.8.0-136.136
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 6.8.0-1061.64
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard6 products
  • linux-aws-6.18< 6.18.31-r0
  • linux-azure-6.18< 6.18.31-r0
  • linux-gcp-6.18< 6.18.31-r0
  • linux-qemu-6.18< 6.18.31-r0
  • linux-qemu-6.18-bootc-boot-installed< 6.18.31-r0
Linux2 products
  • linux≥ 7e6526404adedf079279aa7aa11722deaca8fe2e, < f8f3bb89ab677db15f9f5250c77af728f9afe995 | ≥ 7e6526404adedf079279aa7aa11722deaca8fe2e, < 2c41283d94af943a05f7f2cc1a01f0c872f3cf43 | ≥ 7e6526404adedf079279aa7aa11722deaca8fe2e, < e62e322ea20be78e346e4b49f9a6b9f03313af4c | ≥ 7e6526404adedf079279aa7aa11722deaca8fe2e, < 58e5735d1a5373652f405a0c16e54ac04aaab0ad | ≥ 7e6526404adedf079279aa7aa11722deaca8fe2e, < 7081d46d32312f1a31f0e0e99c6835a394037599 | 4.19
  • linux_kernel≥ 4.19, < 6.12.83 | ≥ 6.13, < 6.18.24 | ≥ 6.19, < 6.19.14 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5 | 7.0:rc6 | 7.0:rc7
Debian1 product
  • linuxAll versions (No fix recorded) | < 6.12.85-1 | < 6.19.14-1

4 vendors · 162 products

References

23 links
Show all 23 references