CVE-2026-52986

Aliases:UBUNTU-CVE-2026-52986DEBIAN-CVE-2026-52986
Advisory lineage Upstream: 0 Downstream: 58
Modified
Published: 24 Jun 2026, 16:29
Last modified:08 Sept 2026, 08:49

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.8 CRITICAL
v3.1 (cve.org)
EPSS Score
0.62% LOW
1% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

24 Jun 2026, 16:29
Published
Vulnerability first disclosed
08 Sept 2026, 08:49
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: don't use simple_strtoul Replace unsafe port parsing in epaddr_len(), ct_sip_parse_header_uri(), and ct_sip_parse_request() with a new sip_parse_port() helper that validates each digit against the buffer limit, eliminating the use of simple_strtoul() which assumes NUL-terminated strings. The previous code dereferenced pointers without bounds checks after sip_parse_addr() and relied on simple_strtoul() on non-NUL-terminated skb data. A port that reaches the buffer limit without a trailing character is also rejected as malformed. Also get rid of all simple_strtoul() usage in conntrack, prefer a stricter version instead. There are intentional changes: - Bail out if number is > UINT_MAX and indicate a failure, same for too long sequences. While we do accept 05535 as port 5535, we will not accept e.g. 'sip:10.0.0.1:005060'. While its syntactically valid under RFC 3261, we should restrict this to not waste cycles when presented with malformed packets with 64k '0' characters. - Force base 10 in ct_sip_parse_numerical_param(). This is used to fetch 'expire=' and 'rports='; both are expected to use base-10. - In nf_nat_sip.c, only accept the parsed value if its within the 1k-64k range. - epaddr_len now returns 0 if the port is invalid, as it already does for invalid ip addresses. This is intentional. nf_conntrack_sip performs lots of guesswork to find the right parts of the message to parse. Being stricter could break existing setups. Connection tracking helpers are designed to allow traffic to pass, not to block it. Based on an earlier patch from Jenny Guanni Qu <qguanni@gmail.com>.

CVSS Metrics

  • v4.0•MEDIUM•Score: 6.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N
  • v3.1•CRITICAL•Score: 9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.62%• Percentile: 48%

Techniques & Countermeasures

  • CWE-476•NULL Pointer Dereference

    The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

  • debian•linux

    < 5.10.259-1 | < 6.1.176-1 | < 6.12.94-1 | < 7.0.10-1

  • debian•linux-6.1

    < 6.1.176-1~deb11u1

  • ubuntu•linux

    all | < 3.13.0-215.266 | < 4.4.0-284.318 | < 4.15.0-254.266 | < 5.4.0-234.254 | < 5.15.0-186.196 | < 6.8.0-136.136 | all | < 7.0.0-28.28

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    all | < 4.4.0-1157.163 | < 4.4.0-1195.210 | < 4.15.0-1195.208 | < 5.4.0-1162.173 | < 5.15.0-1112.119 | < 6.8.0-1061.64 | all | < 7.0.0-1009.9

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    < 5.15.0-1112.119~20.04.1

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    all | < 5.4.0-1162.173~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.14

    all

  • ubuntu•linux-aws-6.17

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    < 6.8.0-1061.64~22.04.1

  • ubuntu•linux-aws-fips

    < 4.15.0-2133.139 | all | < 5.4.0-1163.174+fips1 | < 5.15.0-1112.119+fips1 | < 6.8.0-1061.64+fips1

  • ubuntu•linux-aws-hwe

    all | < 4.15.0-1195.208~16.04.1

  • ubuntu•linux-azure

    all | < 4.15.0-1205.220~14.04.1 | < 4.15.0-1205.220~16.04.1 | all | < 5.4.0-1167.173 | < 5.15.0-1117.126 | < 6.8.0-1063.71 | all | < 7.0.0-1010.10

  • ubuntu•linux-azure-4.15

    < 4.15.0-1205.220

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    < 5.15.0-1117.126~20.04.1

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    all | < 5.4.0-1167.173~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.14

    all

  • ubuntu•linux-azure-6.17

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    < 6.8.0-1063.71~22.04.1

  • ubuntu•linux-azure-7.0

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | < 5.15.0-1117.126 | < 6.8.0-1062.69 | all | < 7.0.0-1009.9

  • ubuntu•linux-azure-fde-5.15

    < 5.15.0-1117.126~20.04.2

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.14

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fde-6.8

    < 6.8.0-1062.69~22.04.1

  • ubuntu•linux-azure-fips

    < 4.15.0-2113.119 | all | < 5.4.0-1167.173+fips1 | < 5.15.0-1117.126+fips1 | < 6.8.0-1063.71+fips2

  • ubuntu•linux-azure-nvidia

    all

  • ubuntu•linux-azure-nvidia-6.14

    all

  • ubuntu•linux-bluefield

    all | all | < 5.4.0-1121.128 | < 5.15.0-1096.98 | < 6.8.0-1028.33

  • ubuntu•linux-fips

    < 4.4.0-1127.134 | all | < 4.15.0-1150.162 | < 5.4.0-1136.146 | < 5.15.0-186.196+fips1 | < 6.8.0-136.136+fips2

  • ubuntu•linux-gcp

    all | < 4.15.0-1188.205~16.04.1 | all | < 5.4.0-1165.174 | < 5.15.0-1112.122 | < 6.8.0-1064.72 | all | < 7.0.0-1008.8

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1188.205

Showing first 50 affected entries in server-rendered view.

References (61)