CVE-2025-37890 remediation guide

Linux Linux, linux kernel, debian linux

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 r...

Open CVE record

ProductLinux Linux, linux kernel, debian linux

Affected versions>= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 273bbcfa53541cde38b2003ad88a59b770306421, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e0cf8ee23e1915431f262a7b2dee0c7a7d699af0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e3e949a39a91d1f829a4890e7dfe9417ac72e4d0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 8df7d37d626430035b413b97cee18396b3450bef, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 6082a87af4c52f58150d40dec1716011d871ac21, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 2e7093c7a8aba5d4f8809f271488e5babe75e202, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < ac39fd4a757584d78ed062d4f6fd913f83bd98b5, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 141d34391abbb315d68556b7c67ad97885407547, >= 5.0, >= 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, 6.15, 11.0

Fixed versions5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6

Priority basisReview · CVSS 7.8 · EPSS 0.17%

Identify the affected asset

Confirm whether Linux Linux, linux kernel, debian linux is installed, record the deployed version and installation path, and identify exposed interfaces.

Record the product name, package or appliance identifier, and installed version.
Identify internet-facing, administrative, API, and internal access paths.
Preserve the pre-change configuration and relevant service logs.

Validate the affected-version match

Compare the deployed version with the affected range: >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 273bbcfa53541cde38b2003ad88a59b770306421, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e0cf8ee23e1915431f262a7b2dee0c7a7d699af0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < e3e949a39a91d1f829a4890e7dfe9417ac72e4d0, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 8df7d37d626430035b413b97cee18396b3450bef, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 6082a87af4c52f58150d40dec1716011d871ac21, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 2e7093c7a8aba5d4f8809f271488e5babe75e202, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < ac39fd4a757584d78ed062d4f6fd913f83bd98b5, >= 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea < 141d34391abbb315d68556b7c67ad97885407547, >= 5.0, >= 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, 6.15, 11.0. Treat incomplete inventory results as unresolved.

Prioritize with independent signals

The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.

Apply supported remediation

Follow the vendor advisory or supported update path. Current fixed-version status: 5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6. Preserve configuration and rollback material before change.

Verify the result

Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.

Confirm the expected version and package state.
Run a functional health check for critical service paths.
Review authentication, error, application, and security monitoring logs.
Reassess exposure if the supported fix cannot be applied.

Operational boundary

This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.