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Detection of Error Condition Without Action The advisory has been revoked - it doesn't affect any version of package libperf  (opens in a new tab)

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  • Snyk IDSNYK-RHEL10-LIBPERF-12630370
  • published12 Sept 2025
  • disclosed11 Sept 2025
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Introduced: 11 Sep 2025

CVE-2025-39766  (opens in a new tab)
CWE-390  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libperf package and not the libperf package as distributed by RHEL.

In the Linux kernel, the following vulnerability has been resolved:

net/sched: Make cake_enqueue return NET_XMIT_CN when past buffer_limit

The following setup can trigger a WARNING in htb_activate due to the condition: !cl->leaf.q->q.qlen

tc qdisc del dev lo root tc qdisc add dev lo root handle 1: htb default 1 tc class add dev lo parent 1: classid 1:1
htb rate 64bit tc qdisc add dev lo parent 1:1 handle f:
cake memlimit 1b ping -I lo -f -c1 -s64 -W0.001 127.0.0.1

This is because the low memlimit leads to a low buffer_limit, which causes packet dropping. However, cake_enqueue still returns NET_XMIT_SUCCESS, causing htb_enqueue to call htb_activate with an empty child qdisc. We should return NET_XMIT_CN when packets are dropped from the same tin and flow.

I do not believe return value of NET_XMIT_CN is necessary for packet drops in the case of ack filtering, as that is meant to optimize performance, not to signal congestion.

References