// For flags

CVE-2025-38067

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

Severity Score

5.5
*CVSS v3

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

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.

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.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
Single
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2025-04-16 CVE Reserved
  • 2025-06-18 CVE Published
  • 2025-07-17 CVE Updated
  • 2025-07-20 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 5.10.240
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 5.10.240"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 5.15.189
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 5.15.189"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 6.1.146
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 6.1.146"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 6.6.99
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 6.6.99"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 6.12.39
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 6.12.39"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 6.14.9
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 6.14.9"
en
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
>= 4.18 < 6.15
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.18 < 6.15"
en
Affected