Vigie VulnDBEuropean-hosted Vulnerability DB

CVE-2025-40271

fs/proc: fix uaf in proc_readdir_de()

At a glance

Severity
HIGH 7.8
EPSS
EPSS 0.46 % · percentile 39 (2026-10-27)
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Deferred

Description

In the Linux kernel, the following vulnerability has been resolved: fs/proc: fix uaf in proc_readdir_de() Pde is erased from subdir rbtree through rb_erase(), but not set the node to EMPTY, which may result in uaf access. We should use RB_CLEAR_NODE() set the erased node to EMPTY, then pde_subdir_next() will return NULL to avoid uaf access. We found an uaf issue while using stress-ng testing, need to run testcase getdent and tun in the same time. The steps of the issue is as follows: 1) use getdent to traverse dir /proc/pid/net/dev_snmp6/, and current pde is tun3; 2) in the [time windows] unregister netdevice tun3 and tun2, and erase them from rbtree. erase tun3 first, and then erase tun2. the pde(tun2) will be released to slab; 3) continue to getdent process, then pde_subdir_next() will return pde(tun2) which is released, it will case uaf access. CPU 0 | CPU 1 ------------------------------------------------------------------------- traverse dir /proc/pid/net/dev_snmp6/ | unregister_netdevice(tun->dev) //tun3 tun2 sys_getdents64() | iterate_dir() | proc_readdir() | proc_readdir_de() | snmp6_unregister_dev() pde_get(de); | proc_remove() read_unlock(&proc_subdir_lock); | remove_proc_subtree() | write_lock(&proc_subdir_lock); [time window] | rb_erase(&root->subdir_node, &parent->subdir); | write_unlock(&proc_subdir_lock); read_lock(&proc_subdir_lock); | next = pde_subdir_next(de); | pde_put(de); | de = next; //UAF | rbtree of dev_snmp6 | pde(tun3) / \ NULL pde(tun2)

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected products

ProductVersions
Linux · Linuxaffected 710585d4922fd315f2cada8fbe550ae8ed23e994 < 1d1596d68a6f11d28f677eedf6cf5b17dbfeb491 ; affected 710585d4922fd315f2cada8fbe550ae8ed23e994 < c81d0385500446efe48c305bbb83d47f2ae23a50 ; affected 710585d4922fd315f2cada8fbe550ae8ed23e994 < 4cba73c4c89219beef7685a47374bf88b1022369 ; affected 710585d4922fd315f2cada8fbe550ae8ed23e994 < 6f2482745e510ae1dacc9b090194b9c5f918d774 ; affected 710585d4922fd315f2cada8fbe550ae8ed23e994 < 67272c11f379d9aa5e0f6b16286b9d89b3f76046 ; affected 710585d4922fd315f2cada8fbe550ae8ed23e994 < 623bb26127fb581a741e880e1e1a47d79aecb6f8
Linux · Linuxaffected 3.19 ; unaffected 0 < 3.19 ; unaffected 5.4.302 ≤ 5.4.* ; unaffected 5.10.247 ≤ 5.10.* ; unaffected 5.15.197 ≤ 5.15.* ; unaffected 6.1.159 ≤ 6.1.*

References

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD