CVE-2026-89543: sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir

Received
AliasesUBUNTU-CVE-2026-89543DEBIAN-CVE-2026-89543
Published 11-09-2026Last modified 21-10-2026

Vulnerability summary

CVE-2026-89543 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10% of scored vulnerabilities.

Overall risk
0/100
0100
Minimal · default modelHow is this calculated?
CVSS score
Not scored
010
No CVSS score recorded
EPSS score
0.21%
0%100%
Low · +0.01 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 1
MGASA-2026-0506OPENSUSE-SU-2026:11880-1

Timeline

  1. 11-09-2026
    PublishedVulnerability first disclosed.
  2. 21-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir Normal client creation goes through rpc_setup_pipedir(), which records clnt->pipefs_sb, but the mount-event path in __rpc_clnt_handle_event() calls rpc_setup_pipedir_sb() directly and never refreshes that field. The umount path also removes the directory without clearing clnt->pipefs_sb. After a late pipefs mount or any remount, rpc_clnt_remove_pipedir() compares the current superblock against a stale pipefs_sb pointer and skips cleanup, leaving pipefs dentries whose inode private data still points at a freed rpc_clnt, leading to a potential use-after-free during subsequent rpc_info_open() or rpc_show_info() calls. Fix this by properly updating clnt->pipefs_sb upon mount events and clearing it during unmount or failure paths.

CVSS metrics

Risk metrics not yet published.

EPSS trend

Probability

0.21%

Chance of exploitation in the next 30 days

Percentile

10%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.20% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu165 products
  • linuxAll versions (No fix recorded)
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linuxAll versions (No fix recorded) | < 6.12.111-1 | < 7.2.6-1
  • linux-6.12< 6.12.111-1~deb12u1
Linux1 product
  • linux≥ cc2e7ebbeb1d0601f7f3c8d93b78fcc03a95e44a, < f99fedfd1dbffe8d20b421c9a7d4655a135d4fcd | ≥ bfca5fb4e97c46503ddfc582335917b0cc228264, < 59527bbfb1eabdb28e95e7c725886cc2c2899cb3 | ≥ bfca5fb4e97c46503ddfc582335917b0cc228264, < e769fcde3cc73e847b1eb3acd40c04a291cb0c0c | ≥ bfca5fb4e97c46503ddfc582335917b0cc228264, < cdf7a233cb94774b0e7df42d9157077983f5022c | ≥ bfca5fb4e97c46503ddfc582335917b0cc228264, < 932a8cf6abb2b2f8677b79153a823108d8861fe2 | 17866066b8ac1cc38fb449670bc15dc9fee4b40a | 7d61d1da2ed1f682c41cae0c8d4719cdaccee5c5 | dedf2a0eb9448ae73b270743e6ea9b108189df46 | 194454afa6aa9d6ed74f0c57127bc8beb27c20df | 7749fd2dbef72a52b5c9ffdbf877691950ed4680 | 1cdb52ffd6600a37bd355d8dce58ecd03e55e618 | ≥ 6.6.3, < 6.6.160 | ≥ 4.19.318, < 4.20 | ≥ 5.4.280, < 5.5 | ≥ 5.10.202, < 5.11 | ≥ 5.15.140, < 5.16 | ≥ 6.1.64, < 6.2 | ≥ 6.5.13, < 6.6 | 6.7

3 vendors · 168 products

References

9 links