9.8

CVE-2026-64535: linux

CVSS: 9.8v3.1CriticalReceived
AliasesUBUNTU-CVE-2026-64535DEBIAN-CVE-2026-64535
Published 27-07-2026Last modified 16-10-2026
Open JSON

Vulnerability summary

CVE-2026-64535 is a critical (CVSS 9.8) vulnerability in linux. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.7% of scored vulnerabilities.

Overall risk
70/100
0100
High · default modelHow is this calculated?
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)
EPSS score
0.55%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 22 · Related 20
MGASA-2026-0336MGASA-2026-0337OPENSUSE-SU-2026:21910-1SUSE-SU-2026:23881-1SUSE-SU-2026:23887-1SUSE-SU-2026:23897-1

Timeline

  1. 27-07-2026
    PublishedVulnerability first disclosed.
  2. 16-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: Fix potential UAF when ddgst mismatch Shivam Kumar found via vulnerability testing: When data digest is enabled on an NVMe/TCP connection and a digest mismatch occurs on a non-final H2C_DATA PDU during an R2T-based data transfer, the digest error handler in nvmet_tcp_try_recv_ddgst() calls nvmet_req_uninit() — which performs percpu_ref_put() on the submission queue — but does NOT mark the command as completed. It does not set cqe->status, does not modify rbytes_done, and does not clear any flag. When the subsequent fatal error triggers queue teardown, nvmet_tcp_uninit_data_in_cmds() iterates all commands, checks nvmet_tcp_need_data_in() for each one, and finds that the already-uninited command still appears to need data (because rbytes_done < transfer_len and cqe->status == 0). It therefore calls nvmet_req_uninit() a second time on the same command — a double percpu_ref_put against a single percpu_ref_get.

CVSS metrics

5 scores · 4 sources · 2 versions

EPSS trend

Probability

0.55%

Chance of exploitation in the next 30 days

Percentile

45%

Versus all other CVEs

30-day change

0.00 pp

From 0.55% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.55%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Ubuntu157 products
  • linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-34.34
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1013.13
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linux< 6.1.180-1 | < 6.12.100-1 | < 7.1.3-1
  • linux-6.12< 6.12.100-1~deb12u1
Linux1 product
  • linux≥ 91edfca6f8b364d60cde3ddefaf7d03ddf35774b, < dfb902462bca478f050224ec7a7195aafa7643b1 | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < 7e558308eba14c8136cb1e615f0c850f76d1fc0a | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < 96fe2513df590e74b04253a45089cae75569570e | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < e091ff83d962f9ed00d9bd70443676de9fe98bdc | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < 6f9442983a3e4227afd1c83a5251ddbca585ea21 | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < 088ee46c18d99baef453afd74181dd40ade044ad | ≥ fda871c0ba5d2eed2cd1c881573168129da70058, < dbbd07d0a7020b80f6a7028e561908f7b83b3d5a | 4b17476d809273617d3317fa0d4ae78aa488d760 | ≥ 5.10.20, < 5.10.265 | ≥ 5.11.3, < 5.12 | 5.12

3 vendors · 160 products

References

27 links
Show all 27 references