{"id":"CVE-2026-99126","state":"PUBLISHED","title":"s390/ctcm: Prevent XID null dereference","description":"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 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.","publishedAt":"2026-10-28T10:34:40.661Z","updatedAt":"2026-10-30T12:41:59.971Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"f9d9e2dadc9fbdfe01aeb6581978c3b59092919e","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"a7c3e1795e4fe5e6680cab7cd7eee0503b00a248","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"c11e435d334e4c311eaaf721e179a5ca6852c221","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"977dac6cc5531a8e058df05b6af94406b940cb9e","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"34fa3607b7604b3052b19cec8b0ad644818cdd2a","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"b264d8422779d69febce914efc47a92a85cc382c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/net/ctcm_mpc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.26","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.26","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/net/ctcm_mpc.c"]}],"references":["https://git.kernel.org/stable/c/f9d9e2dadc9fbdfe01aeb6581978c3b59092919e","https://git.kernel.org/stable/c/a7c3e1795e4fe5e6680cab7cd7eee0503b00a248","https://git.kernel.org/stable/c/c11e435d334e4c311eaaf721e179a5ca6852c221","https://git.kernel.org/stable/c/977dac6cc5531a8e058df05b6af94406b940cb9e","https://git.kernel.org/stable/c/1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213","https://git.kernel.org/stable/c/34fa3607b7604b3052b19cec8b0ad644818cdd2a","https://git.kernel.org/stable/c/8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab","https://git.kernel.org/stable/c/b264d8422779d69febce914efc47a92a85cc382c"],"weaknesses":[],"ingestedAt":"2026-10-30T13:02:04.640Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/99xxx/CVE-2026-99126.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-99126","state":"PUBLISHED","datePublished":"2026-10-28T10:34:40.661Z","dateUpdated":"2026-10-30T12:41:59.971Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.393Z"},"containers":{"cna":{"title":"s390/ctcm: Prevent XID null dereference","descriptions":[{"lang":"en","value":"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 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."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"f9d9e2dadc9fbdfe01aeb6581978c3b59092919e","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"a7c3e1795e4fe5e6680cab7cd7eee0503b00a248","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"c11e435d334e4c311eaaf721e179a5ca6852c221","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"977dac6cc5531a8e058df05b6af94406b940cb9e","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"1525fb6e2f9f9a2c8c8723ee0959b1130a6b8213","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"34fa3607b7604b3052b19cec8b0ad644818cdd2a","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"8a2f7a4ad1d81612fa65bfa4d392ba1bb2f5eeab","versionType":"git"},{"version":"293d984f0e3604c04dcdbf00117ddc1e5d4b1909","status":"affected","lessThan":"b264d8422779d69febce914efc47a92a85cc382c","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/net/ctcm_mpc.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.26","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.26","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.161","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.115","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.59","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.13","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/s390/net/ctcm_mpc.c"]}],"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"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:41:59.971Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.6.161"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.12.115"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"6.18.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"7.2.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.26","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}