5.5

CVE-2026-31428: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD

Modified
AliasesUBUNTU-CVE-2026-31428DEBIAN-CVE-2026-31428
Published 13-04-2026Last modified 15-10-2026

Vulnerability summary

CVE-2026-31428 is a medium (CVSS 5.5) Use of Uninitialized Resource vulnerability in linux. EPSS estimates a 0.13% chance of exploitation in the next 30 days, higher than 2.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.13%
0%100%
Low · -0.05 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 31 · Related 29
MGASA-2026-0108MGASA-2026-0110SUSE-SU-2026:21834-1SUSE-SU-2026:2238-1USN-8567-1USN-8574-1

Timeline

  1. 13-04-2026
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_log: fix uninitialized padding leak in NFULA_PAYLOAD __build_packet_message() manually constructs the NFULA_PAYLOAD netlink attribute using skb_put() and skb_copy_bits(), bypassing the standard nla_reserve()/nla_put() helpers. While nla_total_size(data_len) bytes are allocated (including NLA alignment padding), only data_len bytes of actual packet data are copied. The trailing nla_padlen(data_len) bytes (1-3 when data_len is not 4-byte aligned) are never initialized, leaking stale heap contents to userspace via the NFLOG netlink socket. Replace the manual attribute construction with nla_reserve(), which handles the tailroom check, header setup, and padding zeroing via __nla_reserve(). The subsequent skb_copy_bits() fills in the payload data on top of the properly initialized attribute.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.13%

Chance of exploitation in the next 30 days

Percentile

3%

Versus all other CVEs

30-day change

Decrease -0.05 pp

From 0.18% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

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≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < 7f3e5d72455936f42709116fabeca3bb216cda62 | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < 21d8efda029948d3666b0db5afcc0d36c0984aae | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < fc961dd7272b5e4a462999635e44a4770d7f2482 | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < a8365d1064ded323797c5e28e91070c52f44b76c | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < a2f6ff3444b663d6cfa63eadd61327a18592885a | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < c9f6c51d36482805ac3ffadb9663fe775a13e926 | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < 7eff72968161fb8ddb26113344de3b92fb7d7ef5 | ≥ df6fb868d6118686805c2fa566e213a8f31c8e4f, < 52025ebaa29f4eb4ed8bf92ce83a68f24ab7fdf7 | 2.6.24
  • linux_kernel≥ 2.6.24, < 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 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3 | 7.0:rc4 | 7.0:rc5
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