CVE-2026-99236: Linux Vulnerability (CVSS 7.8)

Description

In the Linux kernel, the following vulnerability has been resolved: tracing: Reject incomplete event filter expressions A non-empty expression normally finishes in predicate_parse()'s inner loop, which resolves the pending logical operators before jumping to finalization. If the input ends after an operator, possibly followed by unary '!' tokens, the outer loop instead falls through with unresolved operator state. For example, "common_pid == 1 || common_pid == 2 &&" leaves prog[0].target equal to -1. The second pass then reads prog[-1] before the forward-jump check can reject it. Depending on adjacent slab contents, it can also copy an out-of-bounds word into a branch target that passes the forward-only check. A self-targeted perf tracepoint counting event can reach this path through PERF_EVENT_IOC_SET_FILTER. Reject the outer-loop fallthrough when a predicate has already been parsed. This ensures that non-empty expressions only reach finalization after the inner loop has resolved their operators. Keep the existing no-filter error for input that has no predicates. Add a regression test for trailing logical operators and unary negations.

Metrics

CVSS 3.1

7.8/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.12%

1.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 4a1a6d35359991c5d47f4bf101cfbe1475c94093; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 2a98f5d4913ec081e08e1075512cb7ec313d9f72; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 15ff3cc7f2beecc3f95d66358f20ad7b057466aa; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < b205ff58e02922ac324f931cf9eb238a3acdb048; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 5a999b5a16530898f0dbe5f8c50fd45ea72e110b; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 1008e9e0b8280d47f1ab5e9c113f666a023a9697; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 64993d970dde2a2da353e9e99595a4fa88ec27d9; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 5bcdf3c18c3471122ee9652b0e2f5cdb718d9a46; >= 80765597bc587feae8dbc8ce97a0f32e12a6e625, < 1fdc4164e488916402badddbb1f51e9380dabb91
Linux	Linux	4.17

References

Timeline

Published: Nov 2, 2026
Last Modified: Nov 3, 2026
Status: Received

Frequently Asked Questions

What is CVE-2026-99236?

In the Linux kernel, the following vulnerability has been resolved: tracing: Reject incomplete event filter expressions A non-empty expression normally finishes in predicate_parse()'s inner loop, which resolves the pending logical operators before jumping to finalization. If the input ends after an operator, possibly followed by unary '!' tokens, the outer loop instead falls through with unresolved operator state. For example, "common_pid == 1 || common_pid == 2 &&" leaves prog[0].target equal to -1. The second pass then reads prog[-1] before the forward-jump check can reject it. Depending on adjacent slab contents, it can also copy an out-of-bounds word into a branch target that passes the forward-only check. A self-targeted perf tracepoint counting event can reach this path through PERF_EVENT_IOC_SET_FILTER. Reject the outer-loop fallthrough when a predicate has already been parsed. This ensures that non-empty expressions only reach finalization after the inner loop has resolved their operators. Keep the existing no-filter error for input that has no predicates. Add a regression test for trailing logical operators and unary negations.

How severe is CVE-2026-99236?

CVE-2026-99236 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.12% probability of exploitation in the next 30 days.

How do I fix CVE-2026-99236?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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