9.8

CVE-2026-31609: smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush()

Modified
AliasesUBUNTU-CVE-2026-31609DEBIAN-CVE-2026-31609CGA-24fw-x52g-fv8f
Published 24-04-2026Last modified 19-10-2026

Vulnerability summary

CVE-2026-31609 is a critical (CVSS 9.8) Double Free vulnerability in linux. EPSS estimates a 0.46% chance of exploitation in the next 30 days, higher than 39.6% 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
0.46%
0%100%
Low · -0.21 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 6 · Related 7
OPENSUSE-SU-2026:10703-1USN-8488-1USN-8488-2USN-8507-1USN-8569-1USN-8603-1

Timeline

  1. 24-04-2026
    PublishedVulnerability first disclosed.
  2. 19-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: avoid double-free in smbd_free_send_io() after smbd_send_batch_flush() smbd_send_batch_flush() already calls smbd_free_send_io(), so we should not call it again after smbd_post_send() moved it to the batch list.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.46%

Chance of exploitation in the next 30 days

Percentile

40%

Versus all other CVEs

30-day change

Decrease -0.21 pp

From 0.67% 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.

Ubuntu98 products
  • linux< 7.0.0-27.27
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 7.0.0-1008.8
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Chainguard11 products
  • linux-aws-6.12All versions (No fix recorded)
  • linux-aws-6.18< 6.18.31-r0
  • linux-azure-6.12All versions (No fix recorded)
  • linux-azure-6.18< 6.18.31-r0
  • linux-gcp-6.12All versions (No fix recorded)
Linux2 products
  • linux≥ cca0526ef2344cab6944d7f441fc24e152da031b, < a9940dcbe5cb92482c04efc7341039ddf7dbf607 | ≥ 37b5c06956183b65e6808b509cf637632016cdf7, < 22b7c1c619d808aec4cad3dc42103345e370d107 | ≥ 21538121efe6c8c5b51c742fa02cbe820bc48714, < f9a162c2bbcd0ac85bd07c5b37cf20286048b65c | ≥ 21538121efe6c8c5b51c742fa02cbe820bc48714, < 27b7c3e916218b5eb2ee350211140e961bfc49be | ≥ 6.18.11, < 6.18.24 | ≥ 6.19.1, < 6.19.14 | 7.0
  • linux_kernel< 6.18.24 | ≥ 6.19, < 6.19.14 | ≥ 7.0, < 7.0.1
Debian1 product
  • linux< 6.19.14-1

4 vendors · 112 products

References

16 links
Show all 16 references