CVE-2026-53269

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-06-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 0

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

netfilter: synproxy: add mutex to guard hook reference counting

As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race each other.

Introduce a mutex to serialize the refcount control blocks access from both frontends. While a per namespace mutex might be more efficient, it is not needed for target/expression like SYNPROXY.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

June 25, 2026

Last Modified

September 8, 2026

Advisory Details (8)

Auto-updated Jul 8, 2026
No patch confirmed yet.
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fbf0591275f50eae5733c3d7a8cd6c1e79933ffa
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/debc57b83d5b323df74bf010c8d50fe26ad2ed6b
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/aaf80701dc2f7a48fe543961e21f8ca3924d587c
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/640441348258220e78daed40528b85b8afcedab6
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/56ffbe3a08c01dcdb0d6adee9ce1e535bfb3b389
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2fcba19caaeb2a33017459d3430f057967bb91b6
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0f8ba5e4c53d2e4a536aa68140beda9fe59b2f88
generic

netfilter: synproxy: add mutex to guard hook reference counting - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/0ec9ddc1bda261a2c57636c74c8b4e53000102c9

Vendor Advisories for CVE-2026-53269(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-26.04-edge (7.0.0-31.31) @ resolute2026-09-08ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1013.13) @ resolute2026-09-08ubuntu
ubuntulinux-tools-gcp-edge (7.0.0-1011.11~24.04.1) @ noble2026-09-08ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(5 across 4 ecosystems)
Debian:11(2)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (54 versions)5.10.259-1—
linux-6.16.1.106-3~deb11u1 ... 6.1.174-1~deb11u1 (20 versions)6.1.176-1~deb11u1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)6.1.176-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.94-1~bpo12+1 (27 versions)6.12.94-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (145 versions)7.0.13-1—

All Vendor Advisories

(4)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 10× in last 7d / 65× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 189 total refreshes for this CVE.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-08 09:43 UTCVendor advisory
  5. 2026-09-08 09:43 UTCGHSA enrichment
  6. 2026-09-08 08:57 UTCEG score recompute
  7. 2026-09-08 08:57 UTCVendor advisory
  8. 2026-09-08 08:57 UTCGHSA enrichment
  9. 2026-09-07 16:01 UTCEPSS rescore
  10. 2026-09-06 13:47 UTCEPSS rescore
  11. 2026-09-04 05:06 UTCEPSS rescore
  12. 2026-09-02 14:12 UTCEPSS rescore
  13. 2026-09-01 13:54 UTCEPSS rescore
  14. 2026-09-01 04:40 UTCEPSS rescore
  15. 2026-08-30 19:36 UTCEG score recompute
  16. 2026-08-30 19:36 UTCVendor advisory
  17. 2026-08-30 19:36 UTCGHSA enrichment
  18. 2026-08-30 19:17 UTCEPSS rescore
  19. 2026-08-30 01:22 UTCEPSS rescore
  20. 2026-08-28 21:41 UTCEPSS rescore
  21. 2026-08-27 23:57 UTCEG score recompute
  22. 2026-08-27 23:57 UTCVendor advisory
  23. 2026-08-27 23:57 UTCGHSA enrichment
  24. 2026-08-27 14:25 UTCEPSS rescore
  25. 2026-08-26 14:46 UTCEPSS rescore
Show 75 more
  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 13:11 UTCEG score recompute
  3. 2026-08-24 13:11 UTCVendor advisory
  4. 2026-08-24 13:11 UTCGHSA enrichment
  5. 2026-08-23 10:27 UTCEG score recompute
  6. 2026-08-23 10:27 UTCVendor advisory
  7. 2026-08-23 10:27 UTCGHSA enrichment
  8. 2026-08-23 00:19 UTCEPSS rescore
  9. 2026-08-22 10:39 UTCEG score recompute
  10. 2026-08-22 10:39 UTCVendor advisory
  11. 2026-08-22 10:39 UTCGHSA enrichment
  12. 2026-08-21 23:49 UTCEPSS rescore
  13. 2026-08-21 06:44 UTCEG score recompute
  14. 2026-08-21 06:44 UTCVendor advisory
  15. 2026-08-21 06:44 UTCGHSA enrichment
  16. 2026-08-20 22:55 UTCEPSS rescore
  17. 2026-08-20 07:05 UTCEG score recompute
  18. 2026-08-20 07:05 UTCVendor advisory
  19. 2026-08-20 07:05 UTCGHSA enrichment
  20. 2026-08-19 17:04 UTCEPSS rescore
  21. 2026-08-19 01:30 UTCEG score recompute
  22. 2026-08-19 01:30 UTCVendor advisory
  23. 2026-08-19 01:30 UTCGHSA enrichment
  24. 2026-08-18 13:48 UTCEPSS rescore
  25. 2026-08-17 13:47 UTCEPSS rescore
  26. 2026-08-16 18:30 UTCEG score recompute
  27. 2026-08-16 18:30 UTCVendor advisory
  28. 2026-08-16 18:30 UTCGHSA enrichment
  29. 2026-08-16 14:56 UTCEPSS rescore
  30. 2026-08-16 02:14 UTCEPSS rescore
  31. 2026-08-15 18:51 UTCEG score recompute
  32. 2026-08-15 18:51 UTCVendor advisory
  33. 2026-08-15 18:51 UTCGHSA enrichment
  34. 2026-08-15 01:30 UTCEPSS rescore
  35. 2026-08-14 19:12 UTCEG score recompute
  36. 2026-08-14 19:12 UTCVendor advisory
  37. 2026-08-14 19:12 UTCGHSA enrichment
  38. 2026-08-13 22:00 UTCEPSS rescore
  39. 2026-08-13 19:33 UTCVendor advisory
  40. 2026-08-13 19:33 UTCGHSA enrichment
  41. 2026-08-12 19:55 UTCEG score recompute
  42. 2026-08-12 19:55 UTCVendor advisory
  43. 2026-08-12 19:55 UTCGHSA enrichment
  44. 2026-08-12 13:51 UTCEPSS rescore
  45. 2026-08-11 20:17 UTCEG score recompute
  46. 2026-08-11 20:17 UTCVendor advisory
  47. 2026-08-11 20:16 UTCGHSA enrichment
  48. 2026-08-11 00:00 UTCEPSS rescore
  49. 2026-08-10 20:38 UTCGHSA enrichment
  50. 2026-08-09 20:59 UTCGHSA enrichment
  51. 2026-08-08 21:21 UTCEG score recompute
  52. 2026-08-08 21:21 UTCVendor advisory
  53. 2026-08-08 21:21 UTCGHSA enrichment
  54. 2026-08-08 16:37 UTCEPSS rescore
  55. 2026-08-07 21:42 UTCEG score recompute
  56. 2026-08-07 21:42 UTCVendor advisory
  57. 2026-08-07 21:42 UTCGHSA enrichment
  58. 2026-08-06 22:04 UTCEG score recompute
  59. 2026-08-06 22:04 UTCVendor advisory
  60. 2026-08-06 22:03 UTCGHSA enrichment
  61. 2026-08-06 13:47 UTCEPSS rescore
  62. 2026-08-05 22:25 UTCEG score recompute
  63. 2026-08-05 22:25 UTCVendor advisory
  64. 2026-08-05 22:25 UTCGHSA enrichment
  65. 2026-08-05 19:17 UTCEPSS rescore
  66. 2026-08-04 22:47 UTCEG score recompute
  67. 2026-08-04 22:47 UTCVendor advisory
  68. 2026-08-04 22:47 UTCGHSA enrichment
  69. 2026-08-04 15:10 UTCEPSS rescore
  70. 2026-08-04 10:39 UTCEPSS rescore
  71. 2026-08-03 23:08 UTCEG score recompute
  72. 2026-08-03 23:08 UTCVendor advisory
  73. 2026-08-03 23:08 UTCGHSA enrichment
  74. 2026-08-03 10:36 UTCEPSS rescore
  75. 2026-08-02 23:30 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-53269?
CVE-2026-53269 is a medium vulnerability published on June 25, 2026. In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: add mutex to guard hook reference counting As the synproxy infrastructure register netfilter hooks on-demand when a user adds the first iptables target or nftables expression, if done concurrently they can race…
When was CVE-2026-53269 disclosed?
CVE-2026-53269 was first published in the National Vulnerability Database on June 25, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53269 actively exploited?
CVE-2026-53269 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.8% of all scored CVEs.
What is the CVSS score of CVE-2026-53269?
CVE-2026-53269 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-53269?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53269, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53269

Explore →

Is Your Infrastructure Affected by CVE-2026-53269?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs