5.5

CVE-2026-64289: iommufd: Set upper bounds on cache invalidation entry_num and entry_len

Analyzed
AliasesUBUNTU-CVE-2026-64289DEBIAN-CVE-2026-64289
Published 25-07-2026Last modified 17-08-2026

Vulnerability summary

CVE-2026-64289 is a medium (CVSS 5.5) vulnerability in linux. EPSS estimates a 0.16% chance of exploitation in the next 30 days, higher than 5.1% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.5, local access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.16%
0%100%
Low · 0.00 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 14 · Related 14
OPENSUSE-SU-2026:11476-1USN-8726-1USN-8726-2USN-8726-3USN-8726-4USN-8727-1

Timeline

  1. 25-07-2026
    PublishedVulnerability first disclosed.
  2. 17-08-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: iommufd: Set upper bounds on cache invalidation entry_num and entry_len iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len, each bounded only by U32_MAX. An entry_len beyond the kernel's struct size makes the copy helper verify the extra bytes are zero, scanning that excess in one uninterruptible pass; a multi-gigabyte value over zeroed user memory trips the soft-lockup watchdog. A large entry_num is the other half, driving the backend invalidation loop with no reschedule. The VT-d nested handler, for one, copies each entry and flushes caches per iteration, pinning the CPU on a non-preemptible kernel. Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request struct, and entry_num under 1 << 19, the order of a hardware invalidation queue and well beyond any real batch, bounding the per-call loop length.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.16%

Chance of exploitation in the next 30 days

Percentile

5%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.16% 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

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Ubuntu142 products
  • linuxAll versions (No fix recorded) | < 6.8.0-147.147 | < 7.0.0-31.31
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 6.8.0-1067.70 | < 7.0.0-1012.12
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linux< 6.12.96-1 | < 7.1.4-1
  • linux-6.12< 6.12.100-1~deb12u1
Linux2 products
  • linux≥ 8c6eabae3807e048b9f17733af5e20500fbf858c, < d2bd041e0efaf7d81789779b135279d18b33d6d5 | ≥ 8c6eabae3807e048b9f17733af5e20500fbf858c, < 32ca4aed2a66205b072fcfecabe220289a8149ff | ≥ 8c6eabae3807e048b9f17733af5e20500fbf858c, < 2c6381d90898089287e0a358f06f89f6b4b389f2 | ≥ 8c6eabae3807e048b9f17733af5e20500fbf858c, < 4d70986002f2f3eaaed89124fb2522bded38b016 | 6.8
  • linux_kernel≥ 6.8, < 6.12.96 | ≥ 6.13, < 6.18.39 | ≥ 6.19, < 7.1.4

3 vendors · 146 products

References

21 links
Show all 21 references