eventpoll: Fix semi-unbounded recursion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-38614
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-08-19 17:15:40 UTC
Updated2026-07-14 13:17:41 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Problem Types: CWE-674

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e 71379495ab70eaba19224bd71b5b9b399eb85e04 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e 1b13b033062824495554e836a1ff5f85ccf6b039 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e 2a0c0c974bea9619c6f41794775ae4b97530e0e6 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e 7a2125962c42d5336ca0495a9ce4cb38a63e9161 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e 3542c90797bc3ab83ebab54b737d751cf3682036 git Not specified
CNA Linux Linux affected 22bacca48a1755f79b7e0f192ddb9fbb7fc6e64e f2e467a48287c868818085aa35389a224d226732 git Not specified
CNA Linux Linux affected 8216e1a0d47cae06a75c42346f19dffe14e42d57 git Not specified
CNA Linux Linux affected 28a92748aa4bc57d35e7b079498b0ac2e7610a37 git Not specified
CNA Linux Linux affected 7eebcd4792c5a341559aed327b6afecbb1c46402 git Not specified
CNA Linux Linux affected 0eccd188cfeaf857a26f2d72941d27d298cf6a54 git Not specified
CNA Linux Linux affected a72affdbb09f3f24f64ffcbbdf62c2e57c58f379 git Not specified
CNA Linux Linux affected 2.6.32.30 2.6.33 semver Not specified
CNA Linux Linux affected 2.6.33.8 2.6.34 semver Not specified
CNA Linux Linux affected 2.6.34.10 2.6.35 semver Not specified
CNA Linux Linux affected 2.6.35.12 2.6.36 semver Not specified
CNA Linux Linux affected 2.6.37.3 2.6.38 semver Not specified
CNA Linux Linux affected 2.6.38 Not specified
CNA Linux Linux unaffected 2.6.38 semver Not specified
CNA Linux Linux unaffected 5.15.190 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.149 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.103 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.43 6.12.* semver Not specified
CNA Linux Linux unaffected 6.15.11 6.15.* semver Not specified
CNA Linux Linux unaffected 6.16.1 6.16.* semver Not specified
CNA Linux Linux unaffected 6.17 * original_commit_for_fix Not specified
ADP Siemens SIMATIC CN 4100 affected V5.0 custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.5 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/ea5f97dbdcb1651581a22bd10afd2f0dd9dc11d6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
lists.debian.org/debian-lts-announce/2025/10/msg00008.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org Third Party Advisory
cert-portal.siemens.com/productcert/html/ssa-082556.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/7a2125962c42d5336ca0495a9ce4cb38a63e9161 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/71379495ab70eaba19224bd71b5b9b399eb85e04 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/1b13b033062824495554e836a1ff5f85ccf6b039 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/2a0c0c974bea9619c6f41794775ae4b97530e0e6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-019113.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
cert-portal.siemens.com/productcert/html/ssa-032379.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/f2e467a48287c868818085aa35389a224d226732 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/3542c90797bc3ab83ebab54b737d751cf3682036 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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