Time-of-check Time-of-use (TOCTOU) Affecting perf6.18-debuginfo package, versions <1:6.18.35-68.127.amzn2023
Threat Intelligence
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Test your applications- Snyk IDSNYK-AMZN2023-PERF618DEBUGINFO-18526081
- published5 Aug 2026
- disclosed19 Jul 2026
Introduced: 19 Jul 2026
NewCVE-2026-64031 (opens in a new tab)How to fix?
Upgrade Amazon-Linux:2023 perf6.18-debuginfo to version 1:6.18.35-68.127.amzn2023 or higher.
This issue was patched in ALAS2023-2026-1881.
NVD Description
Note: Versions mentioned in the description apply only to the upstream perf6.18-debuginfo package and not the perf6.18-debuginfo package as distributed by Amazon-Linux.
See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
erofs: fix managed cache race for unaligned extents
After unaligned compressed extents were introduced, the following race could occur:
[Thread 1] [Thread 2] (z_erofs_fill_bio_vec) <handle a Z_EROFS_PREALLOCATED_FOLIO folio> ... filemap_add_folio (1) (z_erofs_bind_cache) <the same folio is found..> .. .. folio_attach_private (2) filemap_add_folio (3) again
Since (1) is executed but (2) hasn't been executed yet, it's possible that another thread finds the same managed folio in z_erofs_bind_cache() for a different pcluster and calls filemap_add_folio() again since folio->private is still Z_EROFS_PREALLOCATED_FOLIO.
Fix this by explicitly clearing folio->private before making the folio visible in the managed cache so that another pcluster can simply wait on the locked managed folio as what we did for other shared cases [1].
This only impacts unaligned data compression (-E48bit with zstd,
for example).
[1] Commit 9e2f9d34dd12 ("erofs: handle overlapped pclusters out of crafted images properly") was originally introduced to handle crafted overlapped extents, but it addresses unaligned extents as well.