CVE-2025-21792

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2025-02-27. 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:

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt

If an AX25 device is bound to a socket by setting the SO_BINDTODEVICE socket option, a refcount leak will occur in ax25_release().

Commit 9fd75b66b8f6 ("ax25: Fix refcount leaks caused by ax25_cb_del()") added decrement of device refcounts in ax25_release(). In order for that to work correctly the refcounts must already be incremented when the device is bound to the socket. An AX25 device can be bound to a socket by either calling ax25_bind() or setting SO_BINDTODEVICE socket option. In both cases the refcounts should be incremented, but in fact it is done only in ax25_bind().

This bug leads to the following issue reported by Syzkaller:

================================================================ refcount_t: decrement hit 0; leaking memory. WARNING: CPU: 1 PID: 5932 at lib/refcount.c:31 refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31 Modules linked in: CPU: 1 UID: 0 PID: 5932 Comm: syz-executor424 Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:refcount_warn_saturate+0x1ed/0x210 lib/refcount.c:31 Call Trace: __refcount_dec include/linux/refcount.h:336 [inline] refcount_dec include/linux/refcount.h:351 [inline] ref_tracker_free+0x710/0x820 lib/ref_tracker.c:236 netdev_tracker_free include/linux/netdevice.h:4156 [inline] netdev_put include/linux/netdevice.h:4173 [inline] netdev_put include/linux/netdevice.h:4169 [inline] ax25_release+0x33f/0xa10 net/ax25/af_ax25.c:1069 __sock_release+0xb0/0x270 net/socket.c:640 sock_close+0x1c/0x30 net/socket.c:1408 ... do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f ... ================================================================

Fix the implementation of ax25_setsockopt() by adding increment of refcounts for the new device bound, and decrement of refcounts for the old unbound device.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
25(Track)
EG Risk 25/100SSVC: 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%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
15%
KEV
Not listed

Published

February 27, 2025

Last Modified

August 5, 2026

Advisory Details (6)

Auto-updated Aug 2, 2026
Patch available.
generic Patch Available

[SECURITY] [DLA 4102-1] linux-6.1 security update

https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html
generic

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/bca0902e61731a75fc4860c8720168d9f1bae3b6
generic

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b58f7ca86a7b8e480c06e30c5163c5d2f4e24023
generic

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/94a0de224ed52eb2ecd4f4cb1b937b674c9fb955
generic

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/90056ece99966182dc0e367f3fd2afab46ada847
generic

ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/470bda72fda0fcf54300466d70ce2de62f7835d2

Vendor Advisories for CVE-2025-21792(1)

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

Patch Availability(10)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-24.04-edge (6.11.0-26.26) @ oracular2026-05-30ubuntu
ubuntulinux-virtual-6.8 (6.8.0-78.78) @ noble2026-05-30ubuntu
ubuntulinux-tools-azure-nvidia-lts-24.04 (6.8.0-1022.23) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1032.33) @ noble2026-05-30ubuntu
ubuntulinux-tools-aws (6.11.0-1014.15) @ oracular2026-05-30ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2028.29) @ noble2026-05-30ubuntu
ubuntulinux-tools-oracle-64k (6.11.0-1016.17) @ oracular2026-05-30ubuntu
ubuntulinux-tools-raspi-6.8 (6.8.0-1035.39) @ noble2026-05-30ubuntu
ubuntulinux-tools-ibm-edge (6.8.0-1033.33~22.04.1) @ jammy2026-05-30ubuntu
linuxKernel @ 6.1.129—osv

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.

Additional Vendor Advisories

(9)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 45× 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 113 total refreshes for this CVE.

  1. 2026-08-07 16:26 UTCEPSS rescore
  2. 2026-08-06 13:46 UTCEPSS rescore
  3. 2026-08-05 19:16 UTCEPSS rescore
  4. 2026-08-05 14:03 UTCEG score recompute
  5. 2026-08-05 14:03 UTCVendor advisory
  6. 2026-08-05 14:02 UTCGHSA enrichment
  7. 2026-08-04 15:09 UTCEPSS rescore
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  12. 2026-07-30 07:19 UTCEG score recompute
  13. 2026-07-30 07:19 UTCVendor advisory
  14. 2026-07-30 07:19 UTCGHSA enrichment
  15. 2026-07-30 01:29 UTCEPSS rescore
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  21. 2026-07-24 13:41 UTCOSV refresh
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  23. 2026-07-23 02:50 UTCEG score recompute
  24. 2026-07-22 14:07 UTCEPSS rescore
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  21. 2026-07-08 15:14 UTCEPSS rescore
  22. 2026-07-07 13:45 UTCEPSS rescore
  23. 2026-07-07 09:21 UTCOSV refresh
  24. 2026-07-06 16:26 UTCEPSS rescore
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  51. 2026-06-19 19:25 UTCEPSS rescore
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  53. 2026-06-18 20:13 UTCOSV refresh
  54. 2026-06-18 17:52 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2025-21792?
CVE-2025-21792 is a medium vulnerability published on February 27, 2025. In the Linux kernel, the following vulnerability has been resolved: ax25: Fix refcount leak caused by setting SO_BINDTODEVICE sockopt If an AX25 device is bound to a socket by setting the SO_BINDTODEVICE socket option, a refcount leak will occur in ax25_release(). Commit 9fd75b66b8f6 ("ax25: Fix…
When was CVE-2025-21792 disclosed?
CVE-2025-21792 was first published in the National Vulnerability Database on February 27, 2025, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2025-21792 actively exploited?
CVE-2025-21792 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 85.3% of all scored CVEs.
What is the CVSS score of CVE-2025-21792?
CVE-2025-21792 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2025-21792?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2025-21792, 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.

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