CVSS base score: 7.8 (High) vendor CNA · v3.1
Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one. Vulnrichment source record →
Vendor: Linux Product: Linux
In the Linux kernel, the following vulnerability has been resolved: tcp: Use refcount_inc_not_zero() in tcp_twsk_unique(). Anderson Nascimento reported a use-after-free splat in tcp_twsk_unique() with nice analysis. Since commit ec94c2696f0b ("tcp/dccp: avoid one atomic operation for timewait hashdance"), inet_twsk_hashdance() sets TIME-WAIT socket's sk_refcnt after putting it into ehash and releasing the bucket lock. Thus, there is a small race window where other threads could try to reuse the port during connect() and call sock_hold() in tcp_twsk_unique() for the TIME-WAIT socket with zero refcnt. If that happens, the refcnt taken by tcp_twsk_unique() is overwritten and sock_put() will cause underflow, triggering a real use-after-free somewhere else. To avoid the use-after-free, we need to use refcount_inc_not_zero() in tcp_twsk_unique() and give up on reusing the port if it returns false. [0]: refcount_t: addition on 0; use-after-free. WARNING: CPU: 0 PID: 1039313 at lib/refcount.c:25 refcount_warn_saturate+0xe5/0x110 CPU: 0 PID: 1039313 Comm: trigger Not tainted 6.8.6-200.fc39.x86_64 #1 Hardware name: VMware, Inc. VMware20,1/440BX Desktop Reference Platform, BIOS VMW201.00V.21805430.B64.2305221830 05/22/2023 RIP: 0010:refcount_warn_saturate+0xe5/0x110 Code: 42 8e ff 0f 0b c3 cc cc cc cc 80 3d aa 13 ea 01 00 0f 85 5e ff ff ff 48 c7 c7 f8 8e b7 82 c6 05 96 13 ea 01 01 e8 7b 42 8e ff <0f> 0b c3 cc cc cc cc 48 c7 c7 50 8f b7 82 c6 05 7a 13 ea 01 01 e8 RSP: 0018:ffffc90006b43b60 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff888009bb3ef0 RCX: 0000000000000027 RDX: ffff88807be218c8 RSI: 0000000000000001 RDI: ffff88807be218c0 RBP: 0000000000069d70 R08: 0000000000000000 R09: ffffc90006b439f0 R10: ffffc90006b439e8 R11: 0000000000000003 R12: ffff8880029ede84 R13: 0000000000004e20 R14: ffffffff84356dc0 R15: ffff888009bb3ef0 FS: 00007f62c10926c0(0000) GS:ffff88807be00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020ccb000 CR3: 000000004628c005 CR4: 0000000000f70ef0 PKRU: 55555554 Call Trace: <TASK> ? refcount_warn_saturate+0xe5/0x110 ? __warn+0x81/0x130 ? refcount_warn_saturate+0xe5/0x110 ? report_bug+0x171/0x1a0 ? refcount_warn_saturate+0xe5/0x110 ? handle_bug+0x3c/0x80 ? exc_invalid_op+0x17/0x70 ? asm_exc_invalid_op+0x1a/0x20 ? refcount_warn_saturate+0xe5/0x110 tcp_twsk_unique+0x186/0x190 __inet_check_established+0x176/0x2d0 __inet_hash_connect+0x74/0x7d0 ? __pfx___inet_check_established+0x10/0x10 tcp_v4_connect+0x278/0x530 __inet_stream_connect+0x10f/0x3d0 inet_stream_connect+0x3a/0x60 __sys_connect+0xa8/0xd0 __x64_sys_connect+0x18/0x20 do_syscall_64+0x83/0x170 entry_SYSCALL_64_after_hwframe+0x78/0x80 RIP: 0033:0x7f62c11a885d Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a3 45 0c 00 f7 d8 64 89 01 48 RSP: 002b:00007f62c1091e58 EFLAGS: 00000296 ORIG_RAX: 000000000000002a RAX: ffffffffffffffda RBX: 0000000020ccb004 RCX: 00007f62c11a885d RDX: 0000000000000010 RSI: 0000000020ccb000 RDI: 0000000000000003 RBP: 00007f62c1091e90 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 00007f62c10926c0 R13: ffffffffffffff88 R14: 0000000000000000 R15: 00007ffe237885b0 </TASK>
No mentions found in monitored research blogs or news feeds.
| Date | Advisory | Issuer |
|---|---|---|
| 2025-08-14 | ICSA-25-226-15: Siemens SINEC OS | CISA |
| 2024-04-11 | ICSA-24-102-01: Siemens SIMATIC S7-1500 TM MFP | CISA |
Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 3 points from 2026-11-05, tracked daily from 2026-11-05; earlier points are weekly, which dates a spike to within a week. Peak probability 0.6% on 2026-11-05.
Check whether a specific version is affected →
What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.
Blind spot. No public detection — verify by version/patch. Nothing in the monitored scanner, IDS, SIEM or offensive-tool collections references this CVE, so exposure has to be established from asset inventory and patch level rather than from a signature.
Coverage across public collections only: Nuclei and OpenVAS NVT (scan);
Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM);
Metasploit, Exploit-DB, public GitHub repositories and NVD exploit references (exploit). Absence
here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by
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still online, contain code, and are starred or at least two weeks old. They are
still not vetted: some are fakes and some are malware. Treat
them as evidence that code was published, not as code to run.
NVD exploit references are links NVD's analysts tag as exploits; they confirm
an exploit was referenced but carry no date. This product uses data from the
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OpenVAS coverage derives from the Greenbone Community Feed, made available
under the Open Database License (ODbL) v1.0;
its individual Vulnerability Tests are licensed
GNU GPL v2.
No exploit-tool sightings recorded for this CVE.
Metasploit is dated by the first commit of the module file, Exploit-DB by its publication date, and GitHub repositories by their creation date. GitHub PoC repositories are filtered (still online, contain code, starred or at least two weeks old) but not vetted: some are fakes and some are malware, so they show that code was published, not that it works or is safe to run. Evidence tiers are explained on the About page.
Where the distribution has shipped a fix, and in which version. Green means the release has resolved it, amber that it is still open. Data from the Debian Security Tracker, used under Debian's MIT / GPLv2+ terms. Debian is upstream of several other distributions, so a fix here often precedes theirs.
| If the asset is | Remediate within | Table 1 row |
|---|---|---|
| Publicly exposed | 60 days | 8 of 16 |
| Not publicly exposed | Fix on system upgrade | 16 of 16 |
BOD 26-04 replaced the single KEV deadline of BOD 22-01 with four inputs: whether the asset is publicly exposed, KEV status, whether exploitation is automatable, and technical impact. Exposure belongs to each agency's asset, not to the CVE, so both outcomes are shown. Automatable and technical impact come from the CISA assessment above. Days are calendar days; for KEV entries the clock starts on the date it was added, and otherwise when the agency identifies the vulnerability on an asset. Agencies make the final exposure call asset by asset, and may set shorter timelines.
CVE.org record → NVD entry → FortiGuard Labs → Rapid7 AttackerKB →