CVE-2026-43284: xfrm: esp: avoid in-place decrypt on shared skb frags
Description
In the Linux kernel, the following vulnerability has been resolved: xfrm: esp: avoid in-place decrypt on shared skb frags MSG_SPLICE_PAGES can attach pages from a pipe directly to an skb. TCP marks such skbs with SKBFL_SHARED_FRAG after skb_splice_from_iter(), so later paths that may modify packet data can first make a private copy. The IPv4/IPv6 datagram append paths did not set this flag when splicing pages into UDP skbs. That leaves an ESP-in-UDP packet made from shared pipe pages looking like an ordinary uncloned nonlinear skb. ESP input then takes the no-COW fast path for uncloned skbs without a frag_list and decrypts in place over data that is not owned privately by the skb. Mark IPv4/IPv6 datagram splice frags with SKBFL_SHARED_FRAG, matching TCP. Also make ESP input fall back to skb_cow_data() when the flag is present, so ESP does not decrypt externally backed frags in place. Private nonlinear skb frags still use the existing fast path. This intentionally does not change ESP output. In esp_output_head(), the path that appends the ESP trailer to existing skb tailroom without calling skb_cow_data() is not reachable for nonlinear skbs: skb_tailroom() returns zero when skb->data_len is nonzero, while ESP tailen is positive. Thus ESP output will either use the separate destination-frag path or fall back to skb_cow_data().
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Status incidents that name it
- · Minor · names this CVE
“Privilege Escalation Vulnerability We have completed our investigation and response to the "DirtyFrag" (CVE-2026-43500, CVE-2026-43284) and "Fragnesia" (CVE-2026-46300) vulnerabilities. We have published documentation articles with detailed guidance on…”
- · Minor · names this CVE
“Privilege Escalation Vulnerability We have completed our investigation and response to the "DirtyFrag" (CVE-2026-43500, CVE-2026-43284) and "Fragnesia" (CVE-2026-46300) vulnerabilities. We have published documentation articles with detailed guidance on…”
- · No impact listed · names this CVE
“Aptible response to CVE-2026-43284 This incident has been resolved. This incident has been resolved. Aptible is aware of “Dirty Frag,” a recently…”
Affected vendors and products
Linux: LinuxRed Hat: NVIDIA for RHEL 10Red Hat: Red Hat Enterprise Linux 10Red Hat: Red Hat Enterprise Linux 10.0 Extended Update SupportRed Hat: Red Hat Enterprise Linux 6Red Hat: Red Hat Enterprise Linux 7Red Hat: Red Hat Enterprise Linux 8Red Hat: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update SupportRed Hat: Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-OnRed Hat: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update SupportRed Hat: Red Hat Enterprise Linux 8.6 Telecommunications Update ServiceRed Hat: Red Hat Enterprise Linux 8.6 Update Services for SAP SolutionsRed Hat: Red Hat Enterprise Linux 8.8 Telecommunications Update ServiceRed Hat: Red Hat Enterprise Linux 8.8 Update Services for SAP SolutionsRed Hat: Red Hat Enterprise Linux 9Red Hat: Red Hat Enterprise Linux 9.0 Update Services for SAP SolutionsRed Hat: Red Hat Enterprise Linux 9.2 Update Services for SAP SolutionsRed Hat: Red Hat Enterprise Linux 9.4 Extended Update SupportRed Hat: Red Hat Enterprise Linux 9.6 Extended Update SupportRed Hat: Red Hat OpenShift Container Platform 4.12Red Hat: Red Hat OpenShift Container Platform 4.13Red Hat: Red Hat OpenShift Container Platform 4.14Red Hat: Red Hat OpenShift Container Platform 4.15Red Hat: Red Hat OpenShift Container Platform 4.16Red Hat: Red Hat OpenShift Container Platform 4.17Red Hat: Red Hat OpenShift Container Platform 4.18Red Hat: Red Hat OpenShift Container Platform 4.19Red Hat: Red Hat OpenShift Container Platform 4.20Red Hat: Red Hat OpenShift Container Platform 4.21Siemens: SIMATIC S7-1500 CPU 1518-4 PN/DP MFPSiemens: SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPSiemens: SIPLUS S7-1500 CPU 1518-4 PN/DP MFP
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- git.kernel.org/stable/c/50ed1e7873100f77abad20fd31c51029bc49cd03 (opens in new tab)
- git.kernel.org/stable/c/52646cbd00e765a6db9c3afe9535f26218276034 (opens in new tab)
- git.kernel.org/stable/c/5d55c7336f8032d434adcc5fab987ccc93a44aec (opens in new tab)
- git.kernel.org/stable/c/71a1d9d985d26716f74d21f18ee8cac821b06e97 (opens in new tab)
- git.kernel.org/stable/c/8253aab4659ca16116b522203c2a6b18dccacea7 (opens in new tab)
- git.kernel.org/stable/c/a6cb440f274a22456ef3e86b457344f1678f38f9 (opens in new tab)
- git.kernel.org/stable/c/ab8b995323e5237041472d07e5055f5f7dcdf15b (opens in new tab)
- git.kernel.org/stable/c/b54edf1e9a3fd3491bdcb82a21f8d21315271e0d (opens in new tab)
- git.kernel.org/stable/c/f4c50a4034e62ab75f1d5cdd191dd5f9c77fdff4 (opens in new tab)
- git.kernel.org/stable/c/fe785bb3a8096dffcc4048a85cd0c83337eeecad (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)