CVE-2023-54069 — ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow
In the Linux kernel, the following vulnerability has been resolved: ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow When we calculate the end position of ext4_free_extent, this position may be exactly where ext4_lblk_t (i.e. uint) overflows. For example, if ac_g_ex.fe_logical is 4294965248 and ac_orig_goal_len is 2048, then the computed end is 0x100000000, which is 0. If ac->ac_o_ex.fe_logical is not the first case of adjusting the best extent, that is, new_bex_end > 0, the following BUG_ON will be triggered: ========================================================= kernel BUG at fs/ext4/mballoc.c:5116! invalid opcode: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 673 Comm: xfs_io Tainted: G E 6.5.0-rc1+ #279 RIP: 0010:ext4_mb_new_inode_pa+0xc5/0x430 Call Trace: <TASK> ext4_mb_use_best_found+0x203/0x2f0 ext4_mb_try_best_found+0x163/0x240 ext4_mb_regular_allocator+0x158/0x1550 ext4_mb_new_blocks+0x86a/0xe10 ext4_ext_map_blocks+0xb0c/0x13a0 ext4_map_blocks+0x2cd/0x8f0 ext4_iomap_begin+0x27b/0x400 iomap_iter+0x222/0x3d0 __iomap_dio_rw+0x243/0xcb0 iomap_dio_rw+0x16/0x80 ========================================================= A simple reproducer demonstrating the problem: mkfs.ext4 -F /dev/sda -b 4096 100M mount /dev/sda /tmp/test fallocate -l1M /tmp/test/tmp fallocate -l10M /tmp/test/file fallocate -i -o 1M -l16777203M /tmp/test/file fsstress -d /tmp/test -l 0 -n 100000 -p 8 & sleep 10 && killall -9 fsstress rm -f /tmp/test/tmp xfs_io -c "open -ad /tmp/test/file" -c "pwrite -S 0xff 0 8192" We simply refactor the logic for adjusting the best extent by adding a temporary ext4_free_extent ex and use extent_logical_end() to avoid overflow, which also simplifies the code.
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)+2
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 |
version cec4ef62b36b04e0bc8905732adab091f4bc1cfdversion 6.4≥ 6.3.4 and < 6.4≥ 4.19.284 and < 4.20≥ 4.14.316 and < 4.15≥ 6.1.30 and < 6.1.61≥ 5.15.113 and < 5.15.138≥ 5.10.181 and < 5.10.200 and 9 more≥ 5.4.244 and < 5.4.260≥ 8659c5f4ffaacbe932849b98462c3d635b4eacea and < 83ecffd40c65844a73c2e93d7c841455786605acversion 25a60b4533268477920faaeebd99e7e69c0735cdversion 46772ab99409cc72241227dd8f5295f358233fda≥ 93cdf49f6eca5e23f6546b8f28457b2e6a6961d9 and < bc056e7163ac7db945366de219745cf94f32a3e6≥ 93cdf49f6eca5e23f6546b8f28457b2e6a6961d9 and < b7e9ec38b6a0beb5a49cd1e76be0a9a07c218e90≥ 9d4430b7f862ce8835ca4e054b6916d15c8e0862 and < fcefddf3a151b2c416b20120c06bb1ba9ad676fb≥ 613f6cde5ebb005a37fda117cdda7b4126170c13 and < f2c3a3aa6f11ad9878dbc3a067b0633e07b586c1≥ fc7237e191b99f88e859316fab2b06c2c26c8344 and < 58fe961c606c446f5612f6897827b1cac42c2e89 |
Vulnerable | CVE Program (cve.org) e CISA ADP |
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.21%
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
6 on the record
- git.kernel.org/stable/c/58fe961c606c446f5612f6897827b1cac42c2e89
- git.kernel.org/stable/c/fcefddf3a151b2c416b20120c06bb1ba9ad676fb
- git.kernel.org/stable/c/83ecffd40c65844a73c2e93d7c841455786605ac
- git.kernel.org/stable/c/bc056e7163ac7db945366de219745cf94f32a3e6
- git.kernel.org/stable/c/f2c3a3aa6f11ad9878dbc3a067b0633e07b586c1
- git.kernel.org/stable/c/b7e9ec38b6a0beb5a49cd1e76be0a9a07c218e90
Elsewhere on this site
Related CVEs (same products)
- Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 11h
- Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 11h
- 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-2023-54069 is "ext4: fix BUG in ext4_mb_new_inode_pa() due to overflow", 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 0.21% 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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