CVE-2025-38614

Advisory lineage Upstream: 0 Downstream: 52
Modified
Published: 19 Aug 2025, 17:03
Last modified:23 May 2026, 16:00

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.03% LOW
0% probability 0.00%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

19 Aug 2025, 17:03
Published
Vulnerability first disclosed
23 May 2026, 16:00
Last Modified
Vulnerability information updated

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.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.03%• Percentile: 10%

Techniques & Countermeasures

  • CWE-674•Uncontrolled Recursion

    The product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.

Affected Systems

  • debian•debian_linux

    11.0

  • linux•linux

    ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < 71379495ab70eaba19224bd71b5b9b399eb85e04 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < 1b13b033062824495554e836a1ff5f85ccf6b039 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < 2a0c0c974bea9619c6f41794775ae4b97530e0e6 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < 7a2125962c42d5336ca0495a9ce4cb38a63e9161 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < 3542c90797bc3ab83ebab54b737d751cf3682036 | ≥ 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e, < f2e467a48287c868818085aa35389a224d226732 | 8216e1a0d47cae06a75c42346f19dffe14e42d57 | 28a92748aa4bc57d35e7b079498b0ac2e7610a37 | 7eebcd4792c5a341559aed327b6afecbb1c46402 | 0eccd188cfeaf857a26f2d72941d27d298cf6a54 | a72affdbb09f3f24f64ffcbbdf62c2e57c58f379 | ≥ 2.6.32.30, < 2.6.33 | ≥ 2.6.33.8, < 2.6.34 | ≥ 2.6.34.10, < 2.6.35 | ≥ 2.6.35.12, < 2.6.36 | ≥ 2.6.37.3, < 2.6.38 | 2.6.38

  • linux•linux_kernel

    ≥ 2.6.32.30, < 2.6.33 | ≥ 2.6.33.8, < 2.6.34 | ≥ 2.6.34.10, < 2.6.35 | ≥ 2.6.35.12, < 2.6.36 | ≥ 2.6.37.3, < 2.6.38 | ≥ 2.6.38.1, < 5.15.190 | ≥ 5.16, < 6.1.149 | ≥ 6.2, < 6.6.103 | ≥ 6.7, < 6.12.43 | ≥ 6.13, < 6.15.11 | ≥ 6.16, < 6.16.1 | 2.6.38 | 2.6.38:rc7 | 2.6.38:rc8

References (10)