5.5

CVE-2025-38067: rseq: Fix segfault on registration when rseq_cs is non-zero

Modified
AliasesUBUNTU-CVE-2025-38067DEBIAN-CVE-2025-38067
Published 18-06-2025Last modified 15-10-2026

Vulnerability summary

CVE-2025-38067 is a medium (CVSS 5.5) vulnerability in debian debian_linux. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 47.7% 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
0.58%
0%100%
Low · +0.01 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 37 · Related 32
DLA-4327-1DLA-4328-1DSA-5973-1DSA-5975-1RHSA-2025:20095USN-7769-1

Timeline

  1. 18-06-2025
    PublishedVulnerability first disclosed.
  2. 15-10-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: rseq: Fix segfault on registration when rseq_cs is non-zero The rseq_cs field is documented as being set to 0 by user-space prior to registration, however this is not currently enforced by the kernel. This can result in a segfault on return to user-space if the value stored in the rseq_cs field doesn't point to a valid struct rseq_cs. The correct solution to this would be to fail the rseq registration when the rseq_cs field is non-zero. However, some older versions of glibc will reuse the rseq area of previous threads without clearing the rseq_cs field and will also terminate the process if the rseq registration fails in a secondary thread. This wasn't caught in testing because in this case the leftover rseq_cs does point to a valid struct rseq_cs. What we can do is clear the rseq_cs field on registration when it's non-zero which will prevent segfaults on registration and won't break the glibc versions that reuse rseq areas on thread creation.

CVSS metrics

4 scores · 3 sources · 2 versions

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

Increase +0.01 pp

From 0.57% 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.

Ubuntu146 products
  • linuxAll versions (No fix recorded) | < 5.15.0-156.166 | < 6.8.0-100.100
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-awsAll versions (No fix recorded) | < 5.15.0-1092.99 | < 6.8.0-1046.49
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian2 products
  • linux< 6.1.147-1 | < 6.12.41-1 | < 6.16.3-1
  • debian_linuxEOL11.0
Linux2 products
  • linux≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < 48900d839a3454050fd5822e34be8d54c4ec9b86 | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < 3e4028ef31b69286c9d4878cee0330235f53f218 | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < b2b05d0dc2f4f0646922068af435aed5763d16ba | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < eaf112069a904b6207b4106ff083e0208232a2eb | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < f004f58d18a2d3dc761cf973ad27b4a5997bd876 | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < 2df285dab00fa03a3ef939b6cb0d0d0aeb0791db | ≥ d7822b1e24f2df5df98c76f0e94a5416349ff759, < fd881d0a085fc54354414aed990ccf05f282ba53 | 4.18
  • linux_kernel≥ 4.18, < 5.10.240 | ≥ 5.11, < 5.15.189 | ≥ 5.16, < 6.1.146 | ≥ 6.2, < 6.6.99 | ≥ 6.7, < 6.12.39 | ≥ 6.13, < 6.14.9

3 vendors · 150 products

References

47 links
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