{"id":"CVE-2026-64028","state":"PUBLISHED","title":"tracing: Avoid NULL return from hist_field_name() on truncation","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Avoid NULL return from hist_field_name() on truncation\n\nhist_field_name() returns \"\" everywhere except the fully-qualified\nVAR_REF/EXPR case, where snprintf() truncation returns NULL early\nand bypasses the bottom NULL->\"\" guard. Callers don't expect NULL:\nstrcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758\nand the strcmp() in the sort-key match loop at :4804 both deref it.\n\nsystem and event_name are bounded by MAX_EVENT_NAME_LEN, but the\nfield name on a VAR_REF is kstrdup'd from a histogram variable\nname parsed out of the trigger string and has no length cap, so\na long enough var name in a fully qualified reference can reach\nthe truncation path.\n\nKeep the length check but leave field_name as \"\" on overflow.","publishedAt":"2026-07-19T15:39:19.102Z","updatedAt":"2026-07-19T15:39:19.102Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2e8578364061c4e88ae33bc20c2d6f64f365f6a2","status":"affected","lessThan":"e3f5d42cdc2f167719564693675f1eead81378ea","versionType":"git"},{"version":"dfd1cd57ee6067301841b7b0967c70f910a51150","status":"affected","lessThan":"37377b39ff86dacbc533275c1155210d4fd5dc91","versionType":"git"},{"version":"e5c223f46c2e0691461dd97510c15e1f77148872","status":"affected","lessThan":"0402a1d3ddec565132867337ed44514a09d84728","versionType":"git"},{"version":"9399a92989354e34086f9a5c379493217df83c5e","status":"affected","lessThan":"e91687643c440ca3997d67646e6f80b92edc6703","versionType":"git"},{"version":"3cb6cb9c5a547a1979ad74f38eefe8e3687d96e0","status":"affected","lessThan":"be4e99038c1603fa6b329d8ee3e364825e17c353","versionType":"git"},{"version":"0402c60abe769098d77f3b3bd1e29a97922b614b","status":"affected","lessThan":"d6c8b3ebdcdb12b59ad4212acb137cc56cae453d","versionType":"git"},{"version":"6929e650db8451a9975ac0a631ba2d6e5d1e80ba","status":"affected","lessThan":"915c1254fe0788abddc31095b360e9dc98907a34","versionType":"git"},{"version":"5ec1d1e97de134beed3a5b08235a60fc1c51af96","status":"affected","lessThan":"576ec047d20b368b43c4d5db98c4f2e0f3c101ec","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.6.141","status":"affected","lessThan":"6.6.142","versionType":"semver"},{"version":"6.12.91","status":"affected","lessThan":"6.12.92","versionType":"semver"},{"version":"6.18.33","status":"affected","lessThan":"6.18.34","versionType":"semver"},{"version":"7.0.10","status":"affected","lessThan":"7.0.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]}],"references":["https://git.kernel.org/stable/c/e3f5d42cdc2f167719564693675f1eead81378ea","https://git.kernel.org/stable/c/37377b39ff86dacbc533275c1155210d4fd5dc91","https://git.kernel.org/stable/c/0402a1d3ddec565132867337ed44514a09d84728","https://git.kernel.org/stable/c/e91687643c440ca3997d67646e6f80b92edc6703","https://git.kernel.org/stable/c/be4e99038c1603fa6b329d8ee3e364825e17c353","https://git.kernel.org/stable/c/d6c8b3ebdcdb12b59ad4212acb137cc56cae453d","https://git.kernel.org/stable/c/915c1254fe0788abddc31095b360e9dc98907a34","https://git.kernel.org/stable/c/576ec047d20b368b43c4d5db98c4f2e0f3c101ec"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:41.951Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64028.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64028","state":"PUBLISHED","datePublished":"2026-07-19T15:39:19.102Z","dateUpdated":"2026-07-19T15:39:19.102Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T07:54:57.028Z"},"containers":{"cna":{"title":"tracing: Avoid NULL return from hist_field_name() on truncation","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ntracing: Avoid NULL return from hist_field_name() on truncation\n\nhist_field_name() returns \"\" everywhere except the fully-qualified\nVAR_REF/EXPR case, where snprintf() truncation returns NULL early\nand bypasses the bottom NULL->\"\" guard. Callers don't expect NULL:\nstrcat(expr, hist_field_name(field, 0)) at trace_events_hist.c:1758\nand the strcmp() in the sort-key match loop at :4804 both deref it.\n\nsystem and event_name are bounded by MAX_EVENT_NAME_LEN, but the\nfield name on a VAR_REF is kstrdup'd from a histogram variable\nname parsed out of the trigger string and has no length cap, so\na long enough var name in a fully qualified reference can reach\nthe truncation path.\n\nKeep the length check but leave field_name as \"\" on overflow."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2e8578364061c4e88ae33bc20c2d6f64f365f6a2","status":"affected","lessThan":"e3f5d42cdc2f167719564693675f1eead81378ea","versionType":"git"},{"version":"dfd1cd57ee6067301841b7b0967c70f910a51150","status":"affected","lessThan":"37377b39ff86dacbc533275c1155210d4fd5dc91","versionType":"git"},{"version":"e5c223f46c2e0691461dd97510c15e1f77148872","status":"affected","lessThan":"0402a1d3ddec565132867337ed44514a09d84728","versionType":"git"},{"version":"9399a92989354e34086f9a5c379493217df83c5e","status":"affected","lessThan":"e91687643c440ca3997d67646e6f80b92edc6703","versionType":"git"},{"version":"3cb6cb9c5a547a1979ad74f38eefe8e3687d96e0","status":"affected","lessThan":"be4e99038c1603fa6b329d8ee3e364825e17c353","versionType":"git"},{"version":"0402c60abe769098d77f3b3bd1e29a97922b614b","status":"affected","lessThan":"d6c8b3ebdcdb12b59ad4212acb137cc56cae453d","versionType":"git"},{"version":"6929e650db8451a9975ac0a631ba2d6e5d1e80ba","status":"affected","lessThan":"915c1254fe0788abddc31095b360e9dc98907a34","versionType":"git"},{"version":"5ec1d1e97de134beed3a5b08235a60fc1c51af96","status":"affected","lessThan":"576ec047d20b368b43c4d5db98c4f2e0f3c101ec","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.6.141","status":"affected","lessThan":"6.6.142","versionType":"semver"},{"version":"6.12.91","status":"affected","lessThan":"6.12.92","versionType":"semver"},{"version":"6.18.33","status":"affected","lessThan":"6.18.34","versionType":"semver"},{"version":"7.0.10","status":"affected","lessThan":"7.0.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/trace/trace_events_hist.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/e3f5d42cdc2f167719564693675f1eead81378ea"},{"url":"https://git.kernel.org/stable/c/37377b39ff86dacbc533275c1155210d4fd5dc91"},{"url":"https://git.kernel.org/stable/c/0402a1d3ddec565132867337ed44514a09d84728"},{"url":"https://git.kernel.org/stable/c/e91687643c440ca3997d67646e6f80b92edc6703"},{"url":"https://git.kernel.org/stable/c/be4e99038c1603fa6b329d8ee3e364825e17c353"},{"url":"https://git.kernel.org/stable/c/d6c8b3ebdcdb12b59ad4212acb137cc56cae453d"},{"url":"https://git.kernel.org/stable/c/915c1254fe0788abddc31095b360e9dc98907a34"},{"url":"https://git.kernel.org/stable/c/576ec047d20b368b43c4d5db98c4f2e0f3c101ec"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-07-19T15:39:19.102Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.141","versionEndExcluding":"6.6.142"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.12.91","versionEndExcluding":"6.12.92"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.18.33","versionEndExcluding":"6.18.34"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"7.0.10","versionEndExcluding":"7.0.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}