VulnerabilityPublished 25 Jun 2026Updated 6 Nov 2026

CVE-2026-53249: Linux kernel · ipv4: restrict IPOPT_SSRR and IPOPT_LSRR options

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c : update Linux kernel when convenient.

Data as of 6 Nov 2026, 16:49 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c, a4f3fd6516920988c47ba8d19714985c40c816a1, 89343ff12b3178fc236fe531a3603e7c97c68278 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c	Fixed in d3915a1f5a4bc0ac911032903c3c6ab8df9fcc7c
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < a4f3fd6516920988c47ba8d19714985c40c816a1	Fixed in a4f3fd6516920988c47ba8d19714985c40c816a1
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 89343ff12b3178fc236fe531a3603e7c97c68278	Fixed in 89343ff12b3178fc236fe531a3603e7c97c68278
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 28f5ad1b4055405eb1616e603fe511ba5e3725e7	Fixed in 28f5ad1b4055405eb1616e603fe511ba5e3725e7
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 8ff85dbabbbfb05e86e6cde31d91ac5782179d4d	Fixed in 8ff85dbabbbfb05e86e6cde31d91ac5782179d4d
LinuxLinux	Affected ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2	Fixed in 4cd6e9ed49347d3a2fdaaf07e32fb524756dddc2

Description

In the Linux kernel, the following vulnerability has been resolved: ipv4: restrict IPOPT_SSRR and IPOPT_LSRR options This patch restricts setting Loose Source and Record Route (LSRR) and Strict Source and Record Route (SSRR) IP options to users with CAP_NET_RAW capability. This prevents unprivileged applications from forcing packets to route through attacker-controlled nodes to leak TCP ISN and possibly other protocol information. While LSRR and SSRR are commonly filtered in many network environments, they may still be supported and forwarded along some network paths. RFC 7126 (Recommendations on Filtering of IPv4 Packets Containing IPv4 Options) recommend to drop these options in 4.3 and 4.4.

References

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