Unknown

CVE-2025-40281 — sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto

In the Linux kernel, the following vulnerability has been resolved: sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto syzbot reported a possible shift-out-of-bounds [1] Blamed commit added rto_alpha_max and rto_beta_max set to 1000. It is unclear if some sctp users are setting very large rto_alpha and/or rto_beta. In order to prevent user regression, perform the test at run time. Also add READ_ONCE() annotations as sysctl values can change under us. [1] UBSAN: shift-out-of-bounds in net/sctp/transport.c:509:41 shift exponent 64 is too large for 32-bit type 'unsigned int' CPU: 0 UID: 0 PID: 16704 Comm: syz.2.2320 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120 ubsan_epilogue lib/ubsan.c:233 [inline] __ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494 sctp_transport_update_rto.cold+0x1c/0x34b net/sctp/transport.c:509 sctp_check_transmitted+0x11c4/0x1c30 net/sctp/outqueue.c:1502 sctp_outq_sack+0x4ef/0x1b20 net/sctp/outqueue.c:1338 sctp_cmd_process_sack net/sctp/sm_sideeffect.c:840 [inline] sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1372 [inline]

Published Dec 6, 2025 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.2% (30-day exploitation probability)+2
Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.22%

ahead of 11% of scored CVEs · Oct 15, 2026

Affects

Linux

CVSS base

—

Score not published yet.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

Yes

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < 0e0413e3315199b23ff4aec295e256034cd0a6e4≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < 834e65be429c0fa4f9bb5945064bd57f18ed2187≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < abb086b9a95d0ed3b757ee59964ba3c4e4b2fc1a≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < d0d858652834dcf531342c82a0428170aa7c2675≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < ed71f801249d2350c77a73dca2c03918a15a62fe≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < 1cfa4eac275cc4875755c1303d48a4ddfe507ca8≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < aaba523dd7b6106526c24b1fd9b5fc35e5aaa88d≥ b58537a1f5629bdc98a8b9dc2051ce0e952f6b4b and < 1534ff77757e44bcc4b98d0196bc5c0052fce5fa and 1 more version 3.16	Vulnerable	CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 0.22%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Not enough vector or weakness data: use the affected application’s logs as a starting point.

application logs

Timeline

What happened to this CVE, newest first.

2026
Record published
Oct 13, 2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Source status changed · → Deferred
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
2025
CVE published
Dec 6, 2025 · Linux

Source activity

Repeated readings are counted rather than listed.

1× References added · Oct 15, 2026 – Oct 15, 2026
1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

11 on the record

github.com/advisories/GHSA-mgqw-v2hw-3wq7
GitHub Security Advisories
git.kernel.org/stable/c/834e65be429c0fa4f9bb5945064bd57f18ed2187
NIST National Vulnerability Database
git.kernel.org/stable/c/aaba523dd7b6106526c24b1fd9b5fc35e5aaa88d
NIST National Vulnerability Database
git.kernel.org/stable/c/abb086b9a95d0ed3b757ee59964ba3c4e4b2fc1a
NIST National Vulnerability Database
git.kernel.org/stable/c/ed71f801249d2350c77a73dca2c03918a15a62fe
NIST National Vulnerability Database
git.kernel.org/stable/c/1534ff77757e44bcc4b98d0196bc5c0052fce5fa
NIST National Vulnerability Database
nvd.nist.gov/vuln/detail/CVE-2025-40281
GitHub Security Advisories
git.kernel.org/stable/c/d0d858652834dcf531342c82a0428170aa7c2675
NIST National Vulnerability Database
git.kernel.org/stable/c/1cfa4eac275cc4875755c1303d48a4ddfe507ca8
NIST National Vulnerability Database
git.kernel.org/stable/c/0e0413e3315199b23ff4aec295e256034cd0a6e4
NIST National Vulnerability Database
cert-portal.siemens.com/productcert/html/ssa-253495.html
NIST National Vulnerability Database

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 9h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 9h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CVSS score published by NVD, the CNA, CISA or GitHub so far.
No fixed version, patch or mitigation documented.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2025-40281 is "sctp: prevent possible shift-out-of-bounds in sctp_transport_update_rto", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.22% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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