Is CVE-2026-43109 in the CISA KEV catalog?

No. CVE-2026-43109 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-43109?

CVE-2026-43109 has a CVSS v3 base score of 7.1 (Moderate).

What is the EPSS score for CVE-2026-43109?

CVE-2026-43109 has an EPSS score of 0.11% (2th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-43109?

Upgrade linux on debian 13 to 6.12.88-1 or later.

CVE & CISA-KEV Catalog

CVE-2026-43109

MEDIUM

7.1

CVSS v3

NVD

Description

In the Linux kernel, the following vulnerability has been resolved: x86: shadow stacks: proper error handling for mmap lock 김영민 reports that shstk_pop_sigframe() doesn't check for errors from mmap_read_lock_killable(), which is a silly oversight, and also shows that we haven't marked those functions with "__must_check", which would have immediately caught it. So let's fix both issues.

How to fix

Remediation Available

linuxDebian

Fixed in:6.12.88-1CVE-2026-43109

Fixed in:6.19.14-1CVE-2026-43109

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H/E:U

Exploit Intelligence

0.11%probability of exploitation in 30 days

2ndpercentile

Low risk: more likely to be exploited than 2% of all known CVEs.

References

Patch3

Other references2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-17.