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 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.
Affected versions
Linux kernel versions
6.0
and later are affected. Fixed in
6.6.144,
6.12.95,
6.18.38,
7.1.3,
7.2-rc1
and their respective stable series.
References
5 totalFrequently asked questions
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What is CVE-2026-53366?
CVE-2026-53366 is a unscored severity Linux kernel vulnerability . It affects Linux kernel versions from 6.0 onward and has been patched in 6.6.144, 6.12.95, 6.18.38 and others. CVE-2026-53366 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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Is there a patch available for CVE-2026-53366?
Yes — CVE-2026-53366 has been patched. Fixed versions include 6.6.144, 6.12.95, 6.18.38 and others. If you are running Linux kernel 6.0 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-53366 actively exploited?
No — CVE-2026-53366 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.