CVE-2026-80793: ipv4: reject undersized MTUs in ip_do_fragment()

mediumCVSS 4.4CVE-2026-80793

Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: medium — CVSS 4.4
Published: 2026-09-08
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80793

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-807930.19% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 9% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-80793	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

unknownMultiples vulnérabilités dans le noyau Linux de Debian LTS (11 septembre 2026)cert-fr-avis
high[UPDATE] [hoch] Linux Kernel: Mehrere Schwachstellencert-bund
unknownCVE-2026-80793: In the Linux kernel, the following vulnerability has been resolved: ipv4: reject undersized MT…nvd

Recent advisories for ipv4

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

unknownCVE-2026-89564: In the Linux kernel, the following vulnerability has been resolved: ip: orphan prefetched skbs…nvd · 2026-09-11
highCVE-2026-80840: ipv6: seg6: clear IPv4 control block on IPIP decapsulationmsrc · 2026-09-08
highexploitedCVE-2026-67277: RouterOS accepts a "related" btest connection before the corresponding primary session has com…nvd · 2026-09-05
unknownCVE-2026-80840: In the Linux kernel, the following vulnerability has been resolved: ipv6: seg6: clear IPv4 con…nvd · 2026-09-04
unknownCVE-2026-80793: In the Linux kernel, the following vulnerability has been resolved: ipv4: reject undersized MT…nvd · 2026-09-04
mediumCVE-2026-84697: Mailpit's IsInternalIP deny list function fails to block the Azure WireServer address 168.63.1…nvd · 2026-09-02