CVE-2025-37913 | net_sched: qfq: Fix double list add in class with netem as child qdisc

In the Linux kernel, the following vulnerability has been resolved: net_sched: qfq: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of qfq, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. This patch checks whether the class was already added to the agg->active list (cl_is_active) before doing the addition to cater for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/

Published: 2025-05-20 Last update: 2025-11-17 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-37913 is rated Low Risk (39.9/100): CVSS High severity, with low exploitation likelihood (EPSS 0.08%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2025-37913

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-16 0.02% 0.08% +0.07%
2 2025-11-18 0.06% 0.02% -0.04%
3 2025-10-28 — 0.06% —

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-37913

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]

Weakness enumeration for CVE-2025-37913

OS Trackers for CVE-2025-37913

vendor priority summary link
debian not yet assigned CVE-2025-37913 not yet assigned priority: Debian including 2 source packages (linux, linux-6.1), 6 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 6. https://security-tracker.debian.org/tracker/CVE-2025-37913
redhat medium — https://access.redhat.com/security/cve/CVE-2025-37913
suse medium — https://www.suse.com/security/cve/CVE-2025-37913/
ubuntu medium CVE-2025-37913 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, released 168, ignored 164, not-affected 46, needed 25, needs-triage 2, pending 1. https://ubuntu.com/security/CVE-2025-37913

Affected software / configurations for CVE-2025-37913

Vendor Product Version Raw CPE
linux linux_kernel >= 5.0.1, < 5.4.294 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.5, < 5.10.238 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.11, < 5.15.182 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 5.16, < 6.1.138 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.2, < 6.6.90 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.7, < 6.12.28 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.14.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:-:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc3:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc4:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc5:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc6:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc7:*:*:*:*:*:*
linux linux_kernel 5.0 cpe:2.3:o:linux:linux_kernel:5.0:rc8:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc1:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc2:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc3:*:*:*:*:*:*
linux linux_kernel 6.15 cpe:2.3:o:linux:linux_kernel:6.15:rc4:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

References for CVE-2025-37913

URL Tags
https://git.kernel.org/stable/c/005a479540478a820c52de098e5e767e63e36f0a Patch
https://git.kernel.org/stable/c/041f410aec2c1751ee22b8b73ba05d38c3a6a602 Patch
https://git.kernel.org/stable/c/0aa23e0856b7cedb3c88d8e3d281c212c7e4fbeb Patch
https://git.kernel.org/stable/c/0bf32d6fb1fcbf841bb9945570e0e2a70072c00f Patch
https://git.kernel.org/stable/c/370218e8ce711684acc4cdd3cc3c6dd7956bc165 Patch
https://git.kernel.org/stable/c/53bc0b55178bd59bdd4bcd16349505cabf54b1a2 Patch
https://git.kernel.org/stable/c/a43783119e01849fbf2fe8855634e8989b240cb4 Patch
https://git.kernel.org/stable/c/f139f37dcdf34b67f5bf92bc8e0f7f6b3ac63aa4 Patch
https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html Mailing List
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Mailing List
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