How severe is CVE-2026-53249?

CVE-2026-53249 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-53249 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-53249?

CVE-2026-53249 primarily affects Linux Linux Kernel. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-53249?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-53249 have an EU (EUVD) identifier?

Yes. CVE-2026-53249 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39200.

When was CVE-2026-53249 published?

CVE-2026-53249 was published on 2026-06-25 and last updated on 2026-07-07.

CVE-2026-53249

CVE-2026-53249 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39200
Affected product: Linux Linux Kernel
Published: 2026-06-25
Last modified: 2026-07-07

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.

Frequently asked questions

What is CVE-2026-53249?: 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.
How severe is CVE-2026-53249?: CVE-2026-53249 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-53249 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53249?: CVE-2026-53249 primarily affects Linux Linux Kernel. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-53249?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-53249 have an EU (EUVD) identifier?: Yes. CVE-2026-53249 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39200.
When was CVE-2026-53249 published?: CVE-2026-53249 was published on 2026-06-25 and last updated on 2026-07-07.

References

Affected products (12)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:2.6.12:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*

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