9.8

CVE-2026-43378: smb: server: fix use-after-free in smb2_open()

Modified
AliasesUBUNTU-CVE-2026-43378DEBIAN-CVE-2026-43378
Published 08-05-2026Last modified 05-08-2026

Vulnerability summary

CVE-2026-43378 is a critical (CVSS 9.8) Use After Free vulnerability in linux. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 23.7% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.31%
0%100%
Low · -0.13 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 24 · Related 29
LSN-0122-1USN-8492-1USN-8492-2USN-8492-3USN-8492-4USN-8492-5

Timeline

  1. 08-05-2026
    PublishedVulnerability first disclosed.
  2. 05-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: server: fix use-after-free in smb2_open() The opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is dereferenced after rcu_read_unlock(), creating a use-after-free window.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.31%

Chance of exploitation in the next 30 days

Percentile

24%

Versus all other CVEs

30-day change

Decrease -0.13 pp

From 0.44% on 04-10-2026

04-10-202603-11-2026

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

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu145 products
  • linux< 5.15.0-187.197 | < 6.8.0-134.134 | < 6.17.0-40.40
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 5.15.0-1113.120 | < 6.8.0-1060.63 | < 6.17.0-1019.19
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Linux2 products
  • linux≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < e1b21e6066615e7d3d3a7aa2677e415e563fd7cc | ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < b720c84087cb547f23ce03eab93568c1769e4556 | ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 54b48ae83de8bb06e65079d96368efe359d4909c | ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 8f5b1a7cb009a93c48e9e334a2f59a660f9afc07 | ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 190e5f808e8058640b408ccfed25440b441a718a | ≥ e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9, < 1e689a56173827669a35da7cb2a3c78ed5c53680 | 5.15
  • linux_kernel≥ 5.15, < 6.1.167 | ≥ 6.2, < 6.6.130 | ≥ 6.7, < 6.12.78 | ≥ 6.13, < 6.18.19 | ≥ 6.19, < 6.19.9 | 7.0:rc1 | 7.0:rc2 | 7.0:rc3
Debian1 product
  • linux< 6.1.170-1 | < 6.12.85-1 | < 6.19.10-1

3 vendors · 148 products

References

39 links
Show all 39 references