CVE-2026-46169 — hfsplus: fix uninit-value by validating catalog record size
In the Linux kernel, the following vulnerability has been resolved: hfsplus: fix uninit-value by validating catalog record size Syzbot reported a KMSAN uninit-value issue in hfsplus_strcasecmp(). The root cause is that hfs_brec_read() doesn't validate that the on-disk record size matches the expected size for the record type being read. When mounting a corrupted filesystem, hfs_brec_read() may read less data than expected. For example, when reading a catalog thread record, the debug output showed: HFSPLUS_BREC_READ: rec_len=520, fd->entrylength=26 HFSPLUS_BREC_READ: WARNING - entrylength (26) < rec_len (520) - PARTIAL READ! hfs_brec_read() only validates that entrylength is not greater than the buffer size, but doesn't check if it's less than expected. It successfully reads 26 bytes into a 520-byte structure and returns success, leaving 494 bytes uninitialized. This uninitialized data in tmp.thread.nodeName then gets copied by hfsplus_cat_build_key_uni() and used by hfsplus_strcasecmp(), triggering the KMSAN warning when the uninitialized bytes are used as array indices in case_fold(). Fix by introducing hfsplus_brec_read_cat() wrapper that: 1. Calls hfs_brec_read() to read the data 2. Validates the record size based on the type field: - Fixed size for folder and file records - Variable size for thread records (depends on string length) 3. Returns -EIO if size doesn't match expected For thread records, check against HFSPLUS_MIN_THREAD_SZ before reading nodeName.length to avoid reading uninitialized data at call sites that don't zero-initialize the entry structure. Also initialize the tmp variable in hfsplus_find_cat() as defensive programming to ensure no uninitialized data even if validation is bypassed.
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 (medium)+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.
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)
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 |
≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 3003dbf62d151d47a6b90f71655292a51a05f244version 2.6.12≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < b6b592275aeff184aa82fcf6abccd833fb71b393≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 93e8d613f1a01b6637f387cc93f184cf7fb881d6≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < a420904450962a562ad053a41a53a27755021b48≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < c91bbd6193c70a02c50c22e0fb1f60c3c5bd053a≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 61a790974ff7e533acbceca06c7d02f22bf96d4d≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 3bc337697c66db2e2a4a94f0509c282c1a014b86 and 1 more≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and < 8be69532e399eec9d9d990f6958b4ff2383b19b3 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
| Linux | Linux Kernel |
≥ 2.6.12.1 and < 6.6.140version 2.6.12-rc5version 2.6.12-rc4version 2.6.12-rc3version 2.6.12-rc2version 2.6.12≥ 6.19 and < 7.0.7≥ 6.13 and < 6.18.30 and 1 more≥ 6.7 and < 6.12.88 |
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 |
|---|---|---|---|---|---|
| 5.5 | CVSS 3.1 | Medium | 1.8 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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 15, 2026 · 3 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 · 5.5
- Source status changed · → Modified
- 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/a420904450962a562ad053a41a53a27755021b48
- git.kernel.org/stable/c/c91bbd6193c70a02c50c22e0fb1f60c3c5bd053a
- git.kernel.org/stable/c/b6b592275aeff184aa82fcf6abccd833fb71b393
- git.kernel.org/stable/c/61a790974ff7e533acbceca06c7d02f22bf96d4d
- git.kernel.org/stable/c/93e8d613f1a01b6637f387cc93f184cf7fb881d6
- git.kernel.org/stable/c/3bc337697c66db2e2a4a94f0509c282c1a014b86
- git.kernel.org/stable/c/3003dbf62d151d47a6b90f71655292a51a05f244
- git.kernel.org/stable/c/8be69532e399eec9d9d990f6958b4ff2383b19b3
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 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-2026-46169 is "hfsplus: fix uninit-value by validating catalog record size", rated Medium. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.5 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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