What’s Vulnerable › Vulnerabilities

CVE-2026-74391: tracing: Bound synthetic-field strings with seq_buf

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-15 · updated 2026-10-30

Description

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 products

• Linux: 4.17 — fixed in 7.2

How to fix

Upgrade to a fixed version: Linux 7.2. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/0c584c27f6649a93ec12061cc779a4bd8f7c1434
• https://git.kernel.org/stable/c/88b901fdc1662b131ff908cbd017333b61e7acc8
• https://git.kernel.org/stable/c/9f8ef2e1e95a42044e614b0a5277e3f53f545135
• https://git.kernel.org/stable/c/baa333b2700a7fa3529d504529c8c10060fd687c
• https://git.kernel.org/stable/c/cf334620036ad2250e008c7e7bb6646a3938b7b0
• https://git.kernel.org/stable/c/f07883450eb14d1cf020b55d9f3a7ec5683bcd26

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