CVE-2025-37890

Advisory lineage Upstream: 0 Downstream: 133
Analyzed
Published: 16 May 2025, 13:01
Last modified:11 May 2026, 21:17

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
v3.1 (nvd)
EPSS Score
0.08% LOW
0% probability +0.05%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

16 May 2025, 13:01
Published
Vulnerability first disclosed
11 May 2026, 21:17
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class with netem as child qdisc As described in Gerrard's report [1], we have a UAF case when an hfsc class has a netem child qdisc. The crux of the issue is that hfsc is assuming that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted the class in the vttree or eltree (which is not true for the netem duplicate case). This patch checks the n_active class variable to make sure that the code won't insert the class in the vttree or eltree twice, catering for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

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: 0.08%• Percentile: 24%

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 Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.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

  • debian•debian_linux

    11.0

  • linux•linux

    ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < 273bbcfa53541cde38b2003ad88a59b770306421 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < e0cf8ee23e1915431f262a7b2dee0c7a7d699af0 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < e3e949a39a91d1f829a4890e7dfe9417ac72e4d0 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < 8df7d37d626430035b413b97cee18396b3450bef | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < 6082a87af4c52f58150d40dec1716011d871ac21 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < 2e7093c7a8aba5d4f8809f271488e5babe75e202 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < ac39fd4a757584d78ed062d4f6fd913f83bd98b5 | ≥ 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea, < 141d34391abbb315d68556b7c67ad97885407547 | 5.0

  • linux•linux_kernel

    ≥ 5.0.1, < 5.4.294 | ≥ 5.5, < 5.10.238 | ≥ 5.11, < 5.15.182 | ≥ 5.16, < 6.1.138 | ≥ 6.2, < 6.6.90 | ≥ 6.7, < 6.12.28 | ≥ 6.13, < 6.14.6 | 5.0 | 5.0:rc3 | 5.0:rc4 | 5.0:rc5 | 5.0:rc6 | 5.0:rc7 | 5.0:rc8 | 6.15:rc1 | 6.15:rc2 | 6.15:rc3 | 6.15:rc4

References (10)