CVE-2026-63971 — sctp: fix race between sctp_wait_for_connect and peeloff
In the Linux kernel, the following vulnerability has been resolved: sctp: fix race between sctp_wait_for_connect and peeloff sctp_wait_for_connect() drops and re-acquires the socket lock while waiting for the association to reach ESTABLISHED state. During this window, another thread can peeloff the association to a new socket via getsockopt(SCTP_SOCKOPT_PEELOFF), changing asoc->base.sk. After re-acquiring the old socket lock, sctp_wait_for_connect() returns success without noticing the migration — the caller then accesses the association under the wrong lock in sctp_datamsg_from_user(). Add the same sk != asoc->base.sk check that sctp_wait_for_sndbuf() already has, returning an error if the association was migrated while we slept.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 0.1% (30-day exploitation probability)+0
- Technical severity (high)+6
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.
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.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
- Documented patch — git.kernel.org (NIST National Vulnerability Database)
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, Linux Linux Kernel).
- Apply the fixed version or the patch documented under Remediation.
- Search available logs for exploit probes matching the vulnerability class (logic error), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 4.16≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < f14fe6395a8b3d961a61e138ad7b36ba3626dd4e≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 6140cfa721451fa6e18e134e709703c2bf34d0fb≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 68667ee4c7dadf7f63167234e2a1af09b3f7874e≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 7d2038d4b80166f7bead8d07eba3b97405816c21≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 634a9af8a26a84d8b0d7b3b643204b344b42d9fb≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 8e9b56051d24540cfbf39194618708c4a7633549≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < bcfeac79af740735ace44008b4a11b8e5add20f5 and 1 more≥ 668c9beb9020d5834ee9e43c208190a07d2b1928 and < 0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 7.1-rc4version 7.1-rc5≥ 4.16 and < 5.10.259version 7.1-rc3version 7.1-rc2version 7.1-rc1≥ 6.19 and < 7.0.12≥ 6.13 and < 6.18.35 and 4 more≥ 6.7 and < 6.12.93≥ 6.2 and < 6.6.143≥ 5.16 and < 6.1.176≥ 5.11 and < 5.15.210 |
Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 7.8 | CVSS 3.1 | High | 1.8 | 5.9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database |
| 7.8 | CVSS 3.1 | High | — | — | Linux via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
Detection
Read off the CVSS vector and the weakness class. Starting points, not tested rules.
- Local/physical vector: focus on endpoint telemetry (EDR) from affected hosts.
Timeline
What happened to this CVE, newest first.
- 2026
- SSVC assessment updated
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.8
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 15, 2026 – Oct 15, 2026
References
8 on the record
- git.kernel.org/stable/c/f14fe6395a8b3d961a61e138ad7b36ba3626dd4e
- git.kernel.org/stable/c/8e9b56051d24540cfbf39194618708c4a7633549
- git.kernel.org/stable/c/bcfeac79af740735ace44008b4a11b8e5add20f5
- git.kernel.org/stable/c/68667ee4c7dadf7f63167234e2a1af09b3f7874e
- git.kernel.org/stable/c/7d2038d4b80166f7bead8d07eba3b97405816c21
- git.kernel.org/stable/c/6140cfa721451fa6e18e134e709703c2bf34d0fb
- git.kernel.org/stable/c/0e0d5bc76fd4267a71334fcc8f1a5fbcf997845d
- git.kernel.org/stable/c/634a9af8a26a84d8b0d7b3b643204b344b42d9fb
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 1d
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 1d
- Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 2d
- Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 2d
- Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 2d
- Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 2d
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 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-2026-63971 is "sctp: fix race between sctp_wait_for_connect and peeloff", rated High. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.8 describes technical severity. EPSS 0.13% 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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