CVE-2026-31778 — ALSA: caiaq: fix stack out-of-bounds read in init_card
In the Linux kernel, the following vulnerability has been resolved: ALSA: caiaq: fix stack out-of-bounds read in init_card The loop creates a whitespace-stripped copy of the card shortname where `len < sizeof(card->id)` is used for the bounds check. Since sizeof(card->id) is 16 and the local id buffer is also 16 bytes, writing 16 non-space characters fills the entire buffer, overwriting the terminating nullbyte. When this non-null-terminated string is later passed to snd_card_set_id() -> copy_valid_id_string(), the function scans forward with `while (*nid && ...)` and reads past the end of the stack buffer, reading the contents of the stack. A USB device with a product name containing many non-ASCII, non-space characters (e.g. multibyte UTF-8) will reliably trigger this as follows: BUG: KASAN: stack-out-of-bounds in copy_valid_id_string sound/core/init.c:696 [inline] BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c sound/core/init.c:718 The off-by-one has been present since commit bafeee5b1f8d ("ALSA: snd_usb_caiaq: give better shortname") from June 2009 (v2.6.31-rc1), which first introduced this whitespace-stripping loop. The original code never accounted for the null terminator when bounding the copy. Fix this by changing the loop bound to `sizeof(card->id) - 1`, ensuring at least one byte remains as the null terminator.
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 0.2% (30-day exploitation probability)+1
- 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.
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 (memory corruption), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Linux | Linux |
version 2.6.31≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 45424e871abf2a152e247a9cff78359f18dd95c0≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 7594a6464873d90fd229e5b94cdd3b92c9feabed≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 3afa2e67f3523a980a2f90fd63c22322ac2b9ce0≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 3178b62e2e31bab39f63d4c8e54bf4ee0a425627≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < a82c1bce2d1299dd3c686a8fe48cf75b79a403c7≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 66194c2575a4f567577ae70b1d7561163ce791a6≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6 and 1 more≥ bafeee5b1f8d32cbf791c322b40a6fa91d8ccf7a and < 02d9c5b0b5553a391448b6d655262bd829f90234 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
version 7.0-rc5version 7.0-rc6≥ 2.6.31 and < 5.10.253version 7.0-rc4version 7.0-rc3version 7.0-rc2version 7.0-rc1≥ 6.19 and < 6.19.12 and 5 more≥ 6.13 and < 6.18.22≥ 6.7 and < 6.12.81≥ 6.2 and < 6.6.134≥ 5.16 and < 6.1.168≥ 5.11 and < 5.15.203 |
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 |
|---|---|---|---|---|---|
| 7.1 | CVSS 3.1 | High | 1.8 | 5.2 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.17%
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.
- Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · linux/linux
- Record published
- Fix documented
- CVSS changed · 7.1
- 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 13, 2026 – Oct 13, 2026
References
8 on the record
- git.kernel.org/stable/c/3afa2e67f3523a980a2f90fd63c22322ac2b9ce0
- git.kernel.org/stable/c/66194c2575a4f567577ae70b1d7561163ce791a6
- git.kernel.org/stable/c/02d9c5b0b5553a391448b6d655262bd829f90234
- git.kernel.org/stable/c/a82c1bce2d1299dd3c686a8fe48cf75b79a403c7
- git.kernel.org/stable/c/7594a6464873d90fd229e5b94cdd3b92c9feabed
- git.kernel.org/stable/c/45424e871abf2a152e247a9cff78359f18dd95c0
- git.kernel.org/stable/c/3f7f8bae0d52cbd07ab04b76b6aac89ef98ee9f6
- git.kernel.org/stable/c/3178b62e2e31bab39f63d4c8e54bf4ee0a425627
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 10h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 10h
- 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 CISA SSVC assessment.
- 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-2026-31778 is "ALSA: caiaq: fix stack out-of-bounds read in init_card", 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 7.1 describes technical severity. EPSS 0.17% 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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