CVE-2023-53813: linux
Vulnerability summary
CVE-2023-53813 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.3% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 9 · Related 8Timeline
- 09-12-2025PublishedVulnerability first disclosed.
- 11-05-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: ext4: fix rbtree traversal bug in ext4_mb_use_preallocated During allocations, while looking for preallocations(PA) in the per inode rbtree, we can't do a direct traversal of the tree because ext4_mb_discard_group_preallocation() can paralelly mark the pa deleted and that can cause direct traversal to skip some entries. This was leading to a BUG_ON() being hit [1] when we missed a PA that could satisfy our request and ultimately tried to create a new PA that would overlap with the missed one. To makes sure we handle that case while still keeping the performance of the rbtree, we make use of the fact that the only pa that could possibly overlap the original goal start is the one that satisfies the below conditions: 1. It must have it's logical start immediately to the left of (ie less than) original logical start. 2. It must not be deleted To find this pa we use the following traversal method: 1. Descend into the rbtree normally to find the immediate neighboring PA. Here we keep descending irrespective of if the PA is deleted or if it overlaps with our request etc. The goal is to find an immediately adjacent PA. 2. If the found PA is on right of original goal, use rb_prev() to find the left adjacent PA. 3. Check if this PA is deleted and keep moving left with rb_prev() until a non deleted PA is found. 4. This is the PA we are looking for. Now we can check if it can satisfy the original request and proceed accordingly. This approach also takes care of having deleted PAs in the tree. (While we are at it, also fix a possible overflow bug in calculating the end of a PA) [1] https://lore.kernel.org/linux-ext4/CA+G9fYv2FRpLqBZf34ZinR8bU2_ZRAUOjKAD3+tKRFaEQHtt8Q@mail.gmail.com/
CVSS metrics
Risk metrics not yet published.
EPSS trend
Probability
0.19%
Chance of exploitation in the next 30 days
Percentile
8%
Versus all other CVEs
30-day change
0.00 pp
From 0.19% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeNo weakness data has been published for this record.
Affected systems
Ubuntu85 products
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
- linux-aws-5.13All versions (No fix recorded)
- linux-aws-5.19All versions (No fix recorded)
Debian1 product
- linux< 6.4.11-1
Linux1 product
- linux≥ 3872778664e36528caf8b27f355e75482f6d562d, < 339fee69a1daa71d6f97e47a867e2c32419a2406 | ≥ 3872778664e36528caf8b27f355e75482f6d562d, < 9d3de7ee192a6a253f475197fe4d2e2af10a731f | 6.4
3 vendors · 87 products