CVE-2026-53366: In the Linux kernel, the following vulnerability has been resolved: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch

highCVSS 7.8CVE-2026-53366

In the Linux kernel, the following vulnerability has been resolved: ipv4: account for fraggap on the paged allocation path In __ip_append_data(), when the paged-allocation branch is taken, alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap, but the fraggap bytes carried over from the previous skb are copied into the new skb's linear area at offset transhdrlen by the subsequent skb_copy_and_csum_bits(). The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic.

Details

Source: NVD Recent CVEs (US · database · site)
Severity: high — CVSS 7.8
Published: 2026-07-16
Last updated: 2026-07-22
Exploitation: Not in CISA KEV at last sync

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-53366

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-2026-533660.17% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 7% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-53366	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 (31 juillet 2026)cert-fr-avis
medium[NEW] [medium] Linux Kernel: Vulnerability allows Denial of Servicecert-bund
unknownMultiple vulnerabilities in Debian LTS Linux kernel (July 24, 2026)cert-fr-avis
highCVE-2026-53366: ipv4: account for fraggap on the paged allocation pathmsrc

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