{"id":"CVE-2026-99126","title":"s390/ctcm: Prevent XID null dereference","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\ns390/ctcm: Prevent XID null dereference\n\nThe mpc_validate_xid() function sets grp->saved_xid2->xid2_flag2 to 0x40\nto signal XID validation error. If peer XID is NULL or…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < f9d9e2dadc9fbdfe01aeb6581978c3b59092919e","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < a7c3e1795e4fe5e6680cab7cd7eee0503b00a248","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < c11e435d334e4c311eaaf721e179a5ca6852c221","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 977dac6cc5531a8e058df05b6af94406b940cb9e","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 34fa3607b7604b3052b19cec8b0ad644818cdd2a","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab","Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < b264d8422779d69febce914efc47a92a85cc382c","Linux 2.6.26"],"published":"2026-10-28","updated":"2026-10-30","sourceUpdated":"2026-10-30T12:41:59.971Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-99126","references":[{"url":"https://git.kernel.org/stable/c/f9d9e2dadc9fbdfe01aeb6581978c3b59092919e"},{"url":"https://git.kernel.org/stable/c/a7c3e1795e4fe5e6680cab7cd7eee0503b00a248"},{"url":"https://git.kernel.org/stable/c/c11e435d334e4c311eaaf721e179a5ca6852c221"},{"url":"https://git.kernel.org/stable/c/977dac6cc5531a8e058df05b6af94406b940cb9e"},{"url":"https://git.kernel.org/stable/c/1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213"},{"url":"https://git.kernel.org/stable/c/34fa3607b7604b3052b19cec8b0ad644818cdd2a"},{"url":"https://git.kernel.org/stable/c/8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab"},{"url":"https://git.kernel.org/stable/c/b264d8422779d69febce914efc47a92a85cc382c"}],"tags":["cve.org"],"epss":0.00177,"epssPercentile":0.07329,"ingestedAt":"2026-10-28T11:09:40.440Z","slug":"CVE-2026-99126","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\ns390/ctcm: Prevent XID null dereference\n\nThe mpc_validate_xid() function sets grp->saved_xid2->xid2_flag2 to 0x40\nto signal XID validation error. If peer XID is NULL or r/w channel\npairing mismatch happens, grp->saved_xid2 is never initialized. An\nattempt to set the flag in such case leads to NULL dereference.\n\nFix this by using the always available priv->xid->xid2_flag2 instead of\ngrp->saved_xid2->xid2_flag2 for validation errors.\n\n## Affected\n\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < f9d9e2dadc9fbdfe01aeb6581978c3b59092919e`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < a7c3e1795e4fe5e6680cab7cd7eee0503b00a248`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < c11e435d334e4c311eaaf721e179a5ca6852c221`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 977dac6cc5531a8e058df05b6af94406b940cb9e`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 34fa3607b7604b3052b19cec8b0ad644818cdd2a`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < 8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab`\n- `Linux >= 293d984f0e3604c04dcdbf00117ddc1e5d4b1909 < b264d8422779d69febce914efc47a92a85cc382c`\n- `Linux 2.6.26`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}