CVE-2026-31608: smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list()
Vulnerability summary
CVE-2026-31608 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.
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?Advisory lineage
Upstream 0 · Downstream 6 · Related 7Timeline
- 24-04-2026PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: smb: server: avoid double-free in smb_direct_free_sendmsg after smb_direct_flush_send_list() smb_direct_flush_send_list() already calls smb_direct_free_sendmsg(), so we should not call it again after post_sendmsg() moved it to the batch list.
CVSS metrics
6 scores · 5 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · ChainguardEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
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≥ 5ef18a2e66f2f33fdac64437bddfb9fe6389fdc7, < 6968c91fab05b8fc4d6700e0cf34472bb422df25 | ≥ 79242e7b6bc63efec28b7c235bc320806afce6c0, < 2ba03f46132b0d1a7bafb86e1ef61951a2254023 | ≥ 34abd408c8ba24d7c97bd02ba874d8c714f49db1, < 830de6eeb9db4cb7e758201fb99328ef4ca4b032 | ≥ 34abd408c8ba24d7c97bd02ba874d8c714f49db1, < 84ff995ae826aa6bbcc6c7b9ea569ff67c021d72 | ≥ 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