CVE-2026-23270

Advisory lineage Upstream: 0 Downstream: 17
Analyzed
Published: 18 Mar 2026, 17:54
Last modified:23 May 2026, 16:04

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (cve.org)
EPSS Score
0.02% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

18 Mar 2026, 17:54
Published
Vulnerability first disclosed
23 May 2026, 16:04
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net/sched: Only allow act_ct to bind to clsact/ingress qdiscs and shared blocks As Paolo said earlier [1]: "Since the blamed commit below, classify can return TC_ACT_CONSUMED while the current skb being held by the defragmentation engine. As reported by GangMin Kim, if such packet is that may cause a UaF when the defrag engine later on tries to tuch again such packet." act_ct was never meant to be used in the egress path, however some users are attaching it to egress today [2]. Attempting to reach a middle ground, we noticed that, while most qdiscs are not handling TC_ACT_CONSUMED, clsact/ingress qdiscs are. With that in mind, we address the issue by only allowing act_ct to bind to clsact/ingress qdiscs and shared blocks. That way it's still possible to attach act_ct to egress (albeit only with clsact). [1] https://lore.kernel.org/netdev/674b8cbfc385c6f37fb29a1de08d8fe5c2b0fbee.1771321118.git.pabeni@redhat.com/ [2] https://lore.kernel.org/netdev/cc6bfb4a-4a2b-42d8-b9ce-7ef6644fb22b@ovn.org/

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS Trends

Current EPSS score: 0.02%• Percentile: 5%

Techniques & Countermeasures

  • CWE-416•Use After Free

    The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected Systems

  • linux•linux

    0b5b831122fc3789fff75be433ba3e4dd7b779d4 | 73f7da5fd124f2cda9161e2e46114915e6e82e97 | 172ba7d46c202e679f3ccb10264c67416aaeb1c4 | ≥ 172ba7d46c202e679f3ccb10264c67416aaeb1c4, < bc4e5bb529823a09f02dbe96169de679a9db26e0 | ≥ 0b5b831122fc3789fff75be433ba3e4dd7b779d4, < fb3c380a54e33d1fd272cc342faa906d787d7ef1 | ≥ 73f7da5fd124f2cda9161e2e46114915e6e82e97, < 5a110ddcc99bda77a28598b3555fe009eaab3828 | ≥ 3f14b377d01d8357eba032b4cabc8c1149b458b6, < 524ce8b4ea8f64900b6c52b6a28df74f6bc0801e | ≥ 3f14b377d01d8357eba032b4cabc8c1149b458b6, < 380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6 | ≥ 3f14b377d01d8357eba032b4cabc8c1149b458b6, < 9deda0fcda5c1f388c5e279541850b71a2ccfcf4 | ≥ 3f14b377d01d8357eba032b4cabc8c1149b458b6, < 11cb63b0d1a0685e0831ae3c77223e002ef18189 | f5346df0591d10bc948761ca854b1fae6d2ef441 | ≥ 5.15.148, < 5.15.203 | ≥ 6.1.75, < 6.1.167 | ≥ 6.6.14, < 6.6.130 | ≥ 6.7.2, < 6.8 | 6.8

  • linux•linux_kernel

    ≥ 5.15.148, < 5.15.203 | ≥ 6.1.75, < 6.1.167 | ≥ 6.6.14, < 6.6.130 | ≥ 6.7.2, < 6.8 | ≥ 6.8, < 6.12.77 | ≥ 6.13, < 6.18.18 | ≥ 6.19, < 6.19.8 | 7.0:rc1 | 7.0:rc2

References (7)