CVE-2025-38614
Description
In the Linux kernel, the following vulnerability has been resolved: eventpoll: Fix semi-unbounded recursion Ensure that epoll instances can never form a graph deeper than EP_MAX_NESTS+1 links. Currently, ep_loop_check_proc() ensures that the graph is loop-free and does some recursion depth checks, but those recursion depth checks don't limit the depth of the resulting tree for two reasons: - They don't look upwards in the tree. - If there are multiple downwards paths of different lengths, only one of the paths is actually considered for the depth check since commit 28d82dc1c4ed ("epoll: limit paths"). Essentially, the current recursion depth check in ep_loop_check_proc() just serves to prevent it from recursing too deeply while checking for loops. A more thorough check is done in reverse_path_check() after the new graph edge has already been created; this checks, among other things, that no paths going upwards from any non-epoll file with a length of more than 5 edges exist. However, this check does not apply to non-epoll files. As a result, it is possible to recurse to a depth of at least roughly 500, tested on v6.15. (I am unsure if deeper recursion is possible; and this may have changed with commit 8c44dac8add7 ("eventpoll: Fix priority inversion problem").) To fix it: 1. In ep_loop_check_proc(), note the subtree depth of each visited node, and use subtree depths for the total depth calculation even when a subtree has already been visited. 2. Add ep_get_upwards_depth_proc() for similarly determining the maximum depth of an upwards walk. 3. In ep_loop_check(), use these values to limit the total path length between epoll nodes to EP_MAX_NESTS edges.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| rhel | 9 | fixed | |
| sles | affected | | |
| rocky | 9 | fixed | |
| debian | bookworm | fixed | 6.1.153-1 |
| debian | forky | fixed | 6.16.3-1 |
| debian | sid | fixed | 6.16.3-1 |
| debian | trixie | fixed | 6.12.43-1 |
| debian | bullseye | fixed | 6.1.153-1~deb11u1 |
| linux-kernel | affected | 2.6.33 | |
| linux-kernel | 2.6.38 | affected | |
| debian | 11.0 | affected | |
| almalinux | 9 | fixed | kernel-debug-devel-matched-5.14.0-570.52.1.el9_6.aarch64.rpm |
References
- https://access.redhat.com/errata/RHSA-2025:17760
- https://git.kernel.org/stable/c/1b13b033062824495554e836a1ff5f85ccf6b039
- https://git.kernel.org/stable/c/2a0c0c974bea9619c6f41794775ae4b97530e0e6
- https://git.kernel.org/stable/c/3542c90797bc3ab83ebab54b737d751cf3682036
- https://git.kernel.org/stable/c/71379495ab70eaba19224bd71b5b9b399eb85e04
- https://git.kernel.org/stable/c/7a2125962c42d5336ca0495a9ce4cb38a63e9161
- https://git.kernel.org/stable/c/ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6
- https://git.kernel.org/stable/c/f2e467a48287c868818085aa35389a224d226732
- https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html
- https://cert-portal.siemens.com/productcert/html/ssa-032379.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://www.suse.com/security/cve/CVE-2025-38614.html
- https://errata.rockylinux.org/RLSA-2025:17760
- https://security-tracker.debian.org/tracker/CVE-2025-38614
- https://bugzilla.redhat.com/2389456
- https://bugzilla.redhat.com/2389491
- https://bugzilla.redhat.com/2394615
- https://bugzilla.redhat.com/2396379
- https://errata.almalinux.org/9/ALSA-2025-17760.html
CWEs
CWE-674
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.