CVE-2018-1091 — In the flush_tmregs_to_thread function in arch/powerpc/kernel/ptrace

In the flush_tmregs_to_thread function in arch/powerpc/kernel/ptrace.c in the Linux kernel before 4.13.5, a guest kernel crash can be triggered from unprivileged userspace during a core dump on a POWER host due to a missing processor feature check and an erroneous use of transact

01What is this vulnerability?

In the flush_tmregs_to_thread function in arch/powerpc/kernel/ptrace.c in the Linux kernel before 4.13.5, a guest kernel crash can be triggered from unprivileged userspace during a core dump on a POWER host due to a missing processor feature check and an erroneous use of transactional memory (TM) instructions in the core dump path, leading to a denial of service.

02Affected products

Vendor	Product	Versions
n	a / Linux kernel v4.13 and newer	Linux kernel v4.13 and newer

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-03-27T21:00:00.000Z
• Last modified: 2024-08-05T03:51:48.251Z

09References

• bugzilla.redhat.com — https://bugzilla.redhat.com/show_bug.cgi?id=1558149
• www.kernel.org — https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.13.5
• marc.info — https://marc.info/?l=linuxppc-embedded&m=150535531910494&w=2
• access.redhat.com — https://access.redhat.com/security/cve/cve-2018-1091
• access.redhat.com — https://access.redhat.com/errata/RHSA-2018:1318
• git.kernel.org — http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c1fa07…
• github.com — https://github.com/torvalds/linux/commit/c1fa0768a8713b135848f78fd43ffc208d8ded7…
• openwall.com — http://openwall.com/lists/oss-security/2018/03/27/4