Out-of-bounds read in Linux kernel - CVE-2026-52986

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Main Vulnerability Database Vulnerabilities #VU135388

Out-of-bounds read in Linux kernel - CVE-2026-52986

Published: June 25, 2026


Vulnerability identifier: #VU135388
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-52986
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to out-of-bounds read in the nf_conntrack_sip SIP message parser when parsing non-NUL-terminated SIP packet data containing crafted port values. A remote attacker can send a specially crafted SIP packet to cause a denial of service.

The issue involves port parsing in epaddr_len(), ct_sip_parse_header_uri(), and ct_sip_parse_request(), where parsing could reach the buffer limit without a trailing character.


Affected software

Linux kernel
Ubuntu
openEuler
linux (Ubuntu package)
linux-aws-hwe (Ubuntu package)
linux-oracle (Ubuntu package)
linux-azure (Ubuntu package)
bpftool
kernel-tools
python3-perf-debuginfo
python3-perf
perf-debuginfo
perf
kernel-tools-devel
kernel-tools-debuginfo
kernel-source
kernel-headers
kernel-devel
kernel-debugsource
kernel-debuginfo
bpftool-debuginfo
kernel
linux-aws (Ubuntu package)
linux-nvidia-tegra (Ubuntu package)
linux-nvidia-tegra-5.15 (Ubuntu package)
linux-intel-iot-realtime (Ubuntu package)
linux-intel-iotg (Ubuntu package)
linux-azure-5.15 (Ubuntu package)
linux-azure-fips (Ubuntu package)
linux-azure-fde (Ubuntu package)
linux-fips (Ubuntu package)
linux-hwe-6.8 (Ubuntu package)
linux-ibm (Ubuntu package)
linux-oracle-6.8 (Ubuntu package)
linux-nvidia (Ubuntu package)
linux-aws-6.8 (Ubuntu package)
linux-azure-fde-6.8 (Ubuntu package)
linux-gcp-fips (Ubuntu package)
linux-oem-7.0 (Ubuntu package)

How to mitigate CVE-2026-52986

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 3.13.0.215.225, 3.13.0-215.266, 4.15.0.254.238, 4.15.0-254.266, 4.15.0.1150.147, 4.15.0-1150.162, 4.15.0.1177.168, 4.15.0-1177.182, 4.15.0.1188.201~16.04.1, 4.15.0-1188.205, 4.15.0.1195.193, 4.15.0-1195.208, 4.15.0.1205.173, 4.15.0-1205.220, 4.15.0.2096.94, 4.15.0-2096.102, 4.15.0.2113.109, 4.15.0-2113.119, 4.15.0.2133.127, 4.15.0-2133.139, 5.15.0.184.155, 5.15.0-184.194, 5.15.0-184.194~20.04.1, 5.15.0.186.166, 5.15.0-186.196, 5.15.0-186.196~20.04.1, 5.15.0.1075.78, 5.15.0-1075.79, 5.15.0.1095.94, 5.15.0-1095.103, 5.15.0.1104.100, 5.15.0-1104.109, 5.15.0.1108.107, 5.15.0-1108.114, 5.15.0.1111.115, 5.15.0-1111.120+fips1, 5.15.0.1112.102, 5.15.0.1112.109, 5.15.0-1112.122, 5.15.0-1112.122+fips1, 6.8.0-136.136, 6.8.0-1046.50, 6.8.0-1059.67, 6.8.0-1064.72, 6.8.0-1064.72~22.04.1, 6.8.1-1056.57, 6.8.1-1056.57~22.04.2, 7.0.0-28.28, 7.0.0-28.28.1, 7.0.0-1003.4, 7.0.0-1008.8
linux-aws-hwe (Ubuntu package) - addressed in versions 4.15.0-254.266~16.04.1, 4.15.0-1188.205~16.04.1, 4.15.0-1195.208~16.04.1, 4.15.0-1205.220~16.04.1
linux-oracle (Ubuntu package) - addressed in versions 4.15.0.1158.163, 4.15.0-1158.169, 4.15.0-1158.169~16.04.1
linux-azure (Ubuntu package) - addressed in versions 4.15.0-1205.220~14.04.1, 5.15.0.1109.105, 5.15.0-1109.115, 5.15.0.1117.115, 5.15.0-1117.126, 6.8.0-1063.71, 6.8.0-1063.71~22.04.1, 7.0.0-1009.9, 7.0.0-1010.10
bpftool - update to 5.10.0-323.0.0.224
kernel-tools - update to 5.10.0-323.0.0.224
python3-perf-debuginfo - update to 5.10.0-323.0.0.224
python3-perf - update to 5.10.0-323.0.0.224
perf-debuginfo - update to 5.10.0-323.0.0.224
perf - update to 5.10.0-323.0.0.224
kernel-tools-devel - update to 5.10.0-323.0.0.224
kernel-tools-debuginfo - update to 5.10.0-323.0.0.224
kernel-source - update to 5.10.0-323.0.0.224
kernel-headers - update to 5.10.0-323.0.0.224
kernel-devel - update to 5.10.0-323.0.0.224
kernel-debugsource - update to 5.10.0-323.0.0.224
kernel-debuginfo - update to 5.10.0-323.0.0.224
bpftool-debuginfo - update to 5.10.0-323.0.0.224
kernel - update to 5.10.0-323.0.0.224
linux-aws (Ubuntu package) - addressed in versions 5.15.0.186.109, 5.15.0-186.196+fips1, 5.15.0.1106.103, 5.15.0-1106.110, 5.15.0.1107.107, 5.15.0-1107.108, 5.15.0.1112.108, 5.15.0.1112.115, 5.15.0-1112.119, 5.15.0-1112.119+fips1, 5.15.0-1112.119~20.04.1, 6.8.0-1061.64+1, 7.0.0-1009.9, 7.0.0-1015.15
linux-nvidia-tegra (Ubuntu package) - addressed in versions 5.15.0-1053.53, 5.15.0.1053.55, 5.15.0.1064.64, 5.15.0-1064.66
linux-nvidia-tegra-5.15 (Ubuntu package) - update to 5.15.0-1064.66~20.04.1
linux-intel-iot-realtime (Ubuntu package) - addressed in versions 5.15.0-1104.106, 5.15.0.1104.108, 5.15.0-1107.113~20.04.1
linux-intel-iotg (Ubuntu package) - addressed in versions 5.15.0.1107.106, 5.15.0-1107.113
linux-azure-5.15 (Ubuntu package) - addressed in versions 5.15.0-1109.115~20.04.1, 5.15.0-1117.126~20.04.1, 5.15.0-1117.126~20.04.2
linux-azure-fips (Ubuntu package) - addressed in versions 5.15.0.1117.102, 5.15.0-1117.126+fips1, 6.8.0-1063.71+fips2
linux-azure-fde (Ubuntu package) - addressed in versions 5.15.0-1117.126, 6.8.0-1062.69
linux-fips (Ubuntu package) - addressed in versions 6.8.0-136.136+fips2, 6.8.0-136.136.2, 6.8.0-136.136.2~22.04.1, 6.8.0-1058.61
linux-hwe-6.8 (Ubuntu package) - update to 6.8.0-136.136~22.04.1
linux-ibm (Ubuntu package) - addressed in versions 6.8.0-1030.31, 6.8.0-1033.34, 6.8.0-1061.62, 6.8.0-1061.62~22.04.1, 7.0.0-1008.8, 7.0.0-1010.10
linux-oracle-6.8 (Ubuntu package) - update to 6.8.0-1058.61~22.04.1
linux-nvidia (Ubuntu package) - addressed in versions 6.8.0-1059.62, 6.8.0-1059.62.1, 6.8.0-1059.62~22.04.1
linux-aws-6.8 (Ubuntu package) - addressed in versions 6.8.0-1061.64+fips1, 6.8.0-1061.64~22.04.1
linux-azure-fde-6.8 (Ubuntu package) - update to 6.8.0-1062.69~22.04.1
linux-gcp-fips (Ubuntu package) - update to 6.8.0-1064.72+fips1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1009.9

External References

Related Security Bulletins