{"id":"CVE-2026-53366","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: account for fraggap on the paged allocation path\n\nIn __ip_append_data(), when the paged-allocation branch is taken,\nalloclen and pagedlen are computed as\n\n\tallocl…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: account for fraggap on the paged allocation path\n\nIn __ip_append_data(), when the paged-allocation branch is taken,\nalloclen and pagedlen are computed as\n\n\tallocl…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-16","updated":"2026-07-18","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53366","references":[{"url":"https://git.kernel.org/stable/c/77798d7be6ef71e72fb6fc8a2901bf74ebc9706f","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a9c24eda24bd15f432e37824e6fc440977cb241c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c04d9ece23deb9e26c19f9ca215e98b3295aa1bb","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ce494707a9c07f27c219ca67f3e138061f53d9b3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/eca856950f7cb1a221e02b99d758409f2c5cec42","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53366.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-53366"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2501252"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-53366"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53366"},{"url":"https://lore.kernel.org/linux-cve-announce/2026071639-CVE-2026-53366-f508@gregkh/T"},{"url":"https://access.redhat.com/errata/RHSA-2026:35840"},{"url":"https://access.redhat.com/errata/RHSA-2026:34911"},{"url":"https://access.redhat.com/errata/RHSA-2026:66180"}],"tags":["nvd","csaf","vex","red-hat"],"epss":0.00171,"epssPercentile":0.06818,"ingestedAt":"2026-07-18T18:24:14.479Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux BaseOS (v. 10)","affected":["enterprise_linux 9","enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_eus_v_10_0","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_eus_v_10_0","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_eus_v_10_0","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_eus_v_10_0","enterprise_linux_real_time_v_10","enterprise_linux_real_time_v_9"],"patched":["enterprise_linux_appstream_eus_v_10_0","enterprise_linux_appstream_v_10","enterprise_linux_appstream_v_9","enterprise_linux_baseos_eus_v_10_0","enterprise_linux_baseos_v_10","enterprise_linux_baseos_v_9","enterprise_linux_codeready_linux_builder_eus_v_10_0","enterprise_linux_codeready_linux_builder_v_10","enterprise_linux_codeready_linux_builder_v_9","enterprise_linux_real_time_for_nfv_eus_v_10_0","enterprise_linux_real_time_for_nfv_v_10","enterprise_linux_real_time_for_nfv_v_9","enterprise_linux_real_time_eus_v_10_0","enterprise_linux_real_time_v_10","enterprise_linux_real_time_v_9"],"cwe":["CWE-131"],"slug":"CVE-2026-53366","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nipv4: account for fraggap on the paged allocation path\n\nIn __ip_append_data(), when the paged-allocation branch is taken,\nalloclen and pagedlen are computed as\n\n\talloclen = fragheaderlen + transhdrlen;\n\tpagedlen = datalen - transhdrlen;\n\ndatalen already includes fraggap, but the fraggap bytes carried over\nfrom the previous skb are copied into the new skb's linear area at\noffset transhdrlen by the subsequent skb_copy_and_csum_bits(). The\nlinear area is therefore undersized by fraggap bytes while pagedlen is\noverstated by the same amount.\n\nThe non-paged branch sets alloclen to fraglen, which already accounts\nfor fraggap because datalen does. Bring the paged branch in line by\nadding fraggap to alloclen and subtracting it from pagedlen.\n\nAfter this adjustment, copy no longer collapses to -fraggap on the\npaged path, so remove the stale comment describing that old arithmetic.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:35840** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-07-06 · [advisory](https://access.redhat.com/errata/RHSA-2026:35840)\n- **RHSA-2026:34911** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-07-02 · [advisory](https://access.redhat.com/errata/RHSA-2026:34911)\n- **RHSA-2026:66180** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-10 · [advisory](https://access.redhat.com/errata/RHSA-2026:66180)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-09-10 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53366.json)","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}