CVE-2023-54021 — ext4: set goal start correctly in ext4_mb_normalize_request
In the Linux kernel, the following vulnerability has been resolved: ext4: set goal start correctly in ext4_mb_normalize_request We need to set ac_g_ex to notify the goal start used in ext4_mb_find_by_goal. Set ac_g_ex instead of ac_f_ex in ext4_mb_normalize_request. Besides we should assure goal start is in range [first_data_block, blocks_count) as ext4_mb_initialize_context does. [ Added a check to make sure size is less than ar->pright; otherwise we could end up passing an underflowed value of ar->pright - size to ext4_get_group_no_and_offset(), which will trigger a BUG_ON later on. - TYT ]
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
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.
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 |
≥ c9de560ded61faa5b754137b7753da252391c55a and < 2479bb6cbdb4d56b807bbe5229e3e26a6f1f4530≥ c9de560ded61faa5b754137b7753da252391c55a and < 390eee955d4de4662db5e3e9e9a9eae020432cb7≥ c9de560ded61faa5b754137b7753da252391c55a and < cee78217a7ae72d11c2e21e1a5263b8044489823≥ c9de560ded61faa5b754137b7753da252391c55a and < 3ca3005b502ca8ea87d6a344323b179b48c4e4a3≥ c9de560ded61faa5b754137b7753da252391c55a and < bc4a3e1d07a86ae5845321d371190244acacb2f2≥ c9de560ded61faa5b754137b7753da252391c55a and < c6bee8970075b256fc1b07bf4873049219380818≥ c9de560ded61faa5b754137b7753da252391c55a and < abb330ffaa3a0ae7ce632e28c9260b461c01f19f≥ c9de560ded61faa5b754137b7753da252391c55a and < b07ffe6927c75d99af534d685282ea188d9f71a6 and 1 moreversion 2.6.25 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.20%
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.
Timeline
What happened to this CVE, newest first.
- 2026
- Record published
- Affected products added · linux/linux
- Source status changed · → Deferred
- Record created in this database
- 2025
- 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/3ca3005b502ca8ea87d6a344323b179b48c4e4a3
- git.kernel.org/stable/c/390eee955d4de4662db5e3e9e9a9eae020432cb7
- git.kernel.org/stable/c/b07ffe6927c75d99af534d685282ea188d9f71a6
- git.kernel.org/stable/c/cee78217a7ae72d11c2e21e1a5263b8044489823
- git.kernel.org/stable/c/2479bb6cbdb4d56b807bbe5229e3e26a6f1f4530
- git.kernel.org/stable/c/abb330ffaa3a0ae7ce632e28c9260b461c01f19f
- git.kernel.org/stable/c/c6bee8970075b256fc1b07bf4873049219380818
- git.kernel.org/stable/c/bc4a3e1d07a86ae5845321d371190244acacb2f2
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 14h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 14h
- 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 CISA SSVC assessment.
- 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-2023-54021 is "ext4: set goal start correctly in ext4_mb_normalize_request", 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 0.20% 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.
Comments
Moderated technical discussion. Read the community guidelines.
No comments yet.
Sign in or create an account to comment and suggest corrections.