CVE-2026-52986: In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: don't use si

Q: How do I fix CVE-2026-52986?

linux kernel: upgrade to 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10. Exact commands for each OS are on this page.

Q: Is CVE-2026-52986 being exploited?

CVE-2026-52986 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-52986 affect?

CVE-2026-52986 affects linux kernel. Severity is critical (CVSS 9.8). 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_pa

Q: How urgent is CVE-2026-52986?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-52986 is a critical-severity flaw (CVSS 9.8) affecting linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 50%)
CISA exploited list	No
Weakness	CWE-476, CWE-125
Published	2026-06-24
Last modified	2026-10-19

Publisher (CNA): kernel.org · Vendor: linux

Last updated 2026-10-19 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-24 17:17 UTCPublished CVE record published
2026-10-19 20:18 UTCUpdated Record last modified

linux linux kernel UPGRADE

Affected: >= 2.6.26 and < 5.10.258 · >= 5.11 and < 5.15.209 · >= 5.16 and < 6.1.175 · >= 6.2 and < 6.6.141 · >= 6.7 and < 6.12.91 · >= 6.13 and < 6.18.33 · >= 6.19 and < 7.0.10 · 7.1 rc1

Fixed in: 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

Fedora 46 · python3.11 · FIXED · 3.11.18-1.fc46 · FEDORA-2026-cc775894f4 · source

sudo dnf upgrade --advisory=FEDORA-2026-cc775894f4

Ubuntu 22.04 · linux · FIXED · 5.15.0-186.196

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.15.0-186.196" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · linux · FIXED · 5.4.0-234.254

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "5.4.0-234.254" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 24.04 · linux · FIXED · 6.8.0-136.136

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.8.0-136.136" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 20.04 · linux-hwe-5.15 · FIXED · 5.15.0-186.196~20.04.1

sudo apt update && sudo apt install --only-upgrade linux-hwe-5.15 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux-hwe-5.15)" ge "5.15.0-186.196~20.04.1" && echo PATCHED || echo STILL-VULNERABLE

Ubuntu 22.04 · linux-hwe-6.8 · FIXED · 6.8.0-136.136~22.04.1

sudo apt update && sudo apt install --only-upgrade linux-hwe-6.8 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux-hwe-6.8)" ge "6.8.0-136.136~22.04.1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · linux · FIXED · 6.1.176-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.1.176-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · linux · FIXED · 6.12.94-1

sudo apt update && sudo apt install --only-upgrade linux dpkg --compare-versions "$(dpkg-query -W -f='${Version}' linux)" ge "6.12.94-1" && echo PATCHED || echo STILL-VULNERABLE

RHEL 8 · kernel-rt · FIXED · kernel-rt-4.18.0-553.162.1.rt7.503.el8_10

sudo dnf upgrade --advisory=RHSA-2026:66324 rpm -q kernel-rt

RHEL 8 · kernel · FIXED · kernel-4.18.0-553.162.1.el8_10

sudo dnf upgrade --advisory=RHSA-2026:66325 rpm -q kernel

RHEL 9 · kernel · FIXED · kernel-5.14.0-687.55.1.el9_8

sudo dnf upgrade --advisory=RHSA-2026:76739 rpm -q kernel

RHEL 10 · kernel · NO FIX YET

RHEL 6 · kernel · DEFERRED

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1894 · source

sudo dnf update --advisory=ALAS2023-2026-1894

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Write-up: cert-portal.siemens.com/productcert/html/ssa-019113.html
Write-up: cert-portal.siemens.com/productcert/html/ssa-457936.html

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-52986?

linux kernel: upgrade to 5.10.258, 5.15.209, 6.1.175, 6.6.141, 6.12.91, 6.18.33, 7.0.10. Exact commands for each OS are on this page.

Is CVE-2026-52986 being exploited?

CVE-2026-52986 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-52986 affect?

CVE-2026-52986 affects linux kernel. Severity is critical (CVSS 9.8). 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_pa

How urgent is CVE-2026-52986?

Priority 60/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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