CVE-2026-74391
In the Linux kernel, the following vulnerability has been resolved: tracing: Bound synthetic-field strings with seq_buf The synthetic field helpers build a prefixed synthetic variable name and a generated hist command in fixed MAX_FILTER_STR_VAL buffers. The current code appends those strings with raw strcat(), so long key lists, field names, or saved filters can run past the end of the staging buffers. Build both strings with seq_buf and propagate -E2BIG if either the synthetic variable name or the generated command exceeds MAX_FILTER_STR_VAL. This keeps the existing tracing-side limit while using the helper intended for bounded command construction. [ sdr: Moved struct seq_buf *s for upside-down x-mas tree formatting ]
Affected versions
Linux kernel versions
4.17
and later are affected. Fixed in
6.6.145,
6.12.97,
6.18.40,
7.1.5,
7.2-rc1
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-74391?
CVE-2026-74391 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 4.17 onward and has been patched in 6.6.145, 6.12.97, 6.18.40 and others. CVE-2026-74391 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-74391?
Yes. CVE-2026-74391 has been patched. Fixed versions include 6.6.145, 6.12.97, 6.18.40 and others. If you are running Linux kernel 4.17 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-74391 actively exploited?
No. CVE-2026-74391 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.