CVE-2026-99112

HIGHCVSS 7.1/10EPSS 0.17%

Last modified

CVE-2026-99112 is a high-severity vulnerability rated 7.1/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flower: validate mask pointer after nla_next() fl_set_enc_opt() iterates the key's nested tunnel-option attributes with nla_for_each_attr() while advancing a single mask pointer via nla_next() at the bottom of each loop, so the mask cursor is driven by the number of key attributes rather than by the mask's own attributes. The nla_ok() added by commit c96adff956191 ("cls_flower: call nla_ok() before nla_next()") only validates the mask pointer that was just consumed; the pointer produced by nla_next() is used by the next iteration (fl_set_geneve_opt() and siblings) without any validation. The mask's nested attributes are validated with NL_VALIDATE_LIBERAL, which merely warns on trailing bytes that do not form a complete attribute. EPSS estimates a 0.17% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flower: validate mask pointer after nla_next() fl_set_enc_opt() iterates the key's nested tunnel-option attributes with nla_for_each_attr() while advancing a single mask pointer via nla_next() at the bottom of each loop, so the mask cursor is driven by the number of key attributes rather than by the mask's own attributes. The nla_ok() added by commit c96adff956191 ("cls_flower: call nla_ok() before nla_next()") only validates the mask pointer that was just consumed; the pointer produced by nla_next() is used by the next iteration (fl_set_geneve_opt() and siblings) without any validation. The mask's nested attributes are validated with NL_VALIDATE_LIBERAL, which merely warns on trailing bytes that do not form a complete attribute. A mask carrying one valid attribute plus 1-3 residue bytes (or a non-aligned attribute length making msk_depth negative) therefore reaches the next iteration with msk_depth != 0, so neither the !msk_depth check in fl_set_enc_opt() nor the !depth check in the per-type helpers fires. nla_type() then reads past the mask payload and nla_parse_nested_deprecated() iterates with an nla_len taken from those bytes, reading well beyond the mask attribute (KASAN: slab-out-of-bounds read in __nla_validate_parse from fl_change()). Validate the advanced mask pointer as well: when the mask is not legitimately exhausted (msk_depth != 0) and the new pointer fails nla_ok(), reject the filter with -EINVAL. An exactly exhausted mask still skips the check, preserving exact-match behaviour for the remaining key attributes.

Metrics

EPSS Probability
0.17%

6.9th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

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

VendorProductVersions
LinuxLinux>= 238b5ebdb6a6e4bc90810b9f8ec0063b3dfda41a, < a9283d006eef7e3b56f0f279a49bb63f6e5e61df; >= c96adff95619178e2118925578343ad54857c80c, < 497944d534ffb1be300365523030c7c6517cbbb6; >= c96adff95619178e2118925578343ad54857c80c, < a55d84907337580d91c0d54779d9d4b934633158; >= c96adff95619178e2118925578343ad54857c80c, < cff9bf34afde46c238189cc6f7690b7e35225df1; >= c96adff95619178e2118925578343ad54857c80c, < 35354bf67aa0f7bace66ffb614906124ed50d59d; >= c96adff95619178e2118925578343ad54857c80c, < 45e60747a9db2307929260d9aa9c1c6cbb70ee77; >= c96adff95619178e2118925578343ad54857c80c, < bb187146c7e5c666874784e4f3fc1bc5126e6e92; >= c96adff95619178e2118925578343ad54857c80c, < fee10655709c5c597e8e9f722f3035d9ea31ff3a; >= 5.10.11, < 5.10.273
LinuxLinux5.11

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-99112?
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_flower: validate mask pointer after nla_next() fl_set_enc_opt() iterates the key's nested tunnel-option attributes with nla_for_each_attr() while advancing a single mask pointer via nla_next() at the bottom of each loop, so the mask cursor is driven by the number of key attributes rather than by the mask's own attributes. The nla_ok() added by commit c96adff956191 ("cls_flower: call nla_ok() before nla_next()") only validates the mask pointer that was just consumed; the pointer produced by nla_next() is used by the next iteration (fl_set_geneve_opt() and siblings) without any validation. The mask's nested attributes are validated with NL_VALIDATE_LIBERAL, which merely warns on trailing bytes that do not form a complete attribute. A mask carrying one valid attribute plus 1-3 residue bytes (or a non-aligned attribute length making msk_depth negative) therefore reaches the next iteration with msk_depth != 0, so neither the !msk_depth check in fl_set_enc_opt() nor the !depth check in the per-type helpers fires. nla_type() then reads past the mask payload and nla_parse_nested_deprecated() iterates with an nla_len taken from those bytes, reading well beyond the mask attribute (KASAN: slab-out-of-bounds read in __nla_validate_parse from fl_change()). Validate the advanced mask pointer as well: when the mask is not legitimately exhausted (msk_depth != 0) and the new pointer fails nla_ok(), reject the filter with -EINVAL. An exactly exhausted mask still skips the check, preserving exact-match behaviour for the remaining key attributes.
How severe is CVE-2026-99112?
CVE-2026-99112 has a CVSS score of 7.1/10 (HIGH severity). The EPSS model estimates a 0.17% probability of exploitation in the next 30 days.
How do I fix CVE-2026-99112?
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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Source: NVD / NIST