{"id":"CVE-2026-62303","state":"PUBLISHED","title":"Pistache: DoS via stack exhaustion in REST router path normalization (regex_replace on long slash runs)","description":"Pistache is a high-performance REST toolkit written in C++. From 0.0.5 through 0.4.26, `SegmentTreeNode::sanitizeResource()` in `src/server/router.cc` uses `std::regex_replace()` with the `//+` expression to collapse consecutive slashes. With libstdc++, a path containing tens of thousands of consecutive slash characters can recurse deeply enough to exhaust the stack and crash the process. `Router::route()`, `Router::addRoute()` and `Router::removeRoute()` reach this normalization. Unauthenticated remote exploitation is conditional on a deployment allowing sufficiently long request paths, such as by increasing `Endpoint::Options::maxRequestSize()` above the default 4096-byte limit or forwarding long paths through a front end. Direct router API use is also affected when attacker-controlled route or resource strings reach the normalizer. Native builds reproduced a crash around 24,000 consecutive slashes, although the exact threshold depends on the stack and standard library; the demonstrated failure is stack exhaustion rather than uninitialized-memory use. A source fix replaces recursive regular-expression normalization with an iterative pass, but no containing repository release was verified as of time of publication.","publishedAt":"2026-10-30T18:58:10.308Z","updatedAt":"2026-10-30T18:58:10.308Z","severity":{"score":5.9,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"GitHub_M"},"assigner":"GitHub_M","products":["pistacheio pistache"],"affected":[{"vendor":"pistacheio","product":"pistache","versions":[{"version":">= 0.0.5, <= 0.4.26","status":"affected"}]}],"references":["https://github.com/pistacheio/pistache/security/advisories/GHSA-q474-pqcp-gqm5","https://github.com/pistacheio/pistache/commit/935461352403696f3ca0dbb9a7de7d2609e7ce91"],"weaknesses":["CWE-400","CWE-674"],"ingestedAt":"2026-10-30T19:04:06.194Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/62xxx/CVE-2026-62303.json","commit":"498f53b27d1d9de6ce17bd324191d270b9adc0e0","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-62303","state":"PUBLISHED","datePublished":"2026-10-30T18:58:10.308Z","dateUpdated":"2026-10-30T18:58:10.308Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-07-13T19:27:58.313Z"},"containers":{"cna":{"title":"Pistache: DoS via stack exhaustion in REST router path normalization (regex_replace on long slash runs)","descriptions":[{"lang":"en","value":"Pistache is a high-performance REST toolkit written in C++. From 0.0.5 through 0.4.26, `SegmentTreeNode::sanitizeResource()` in `src/server/router.cc` uses `std::regex_replace()` with the `//+` expression to collapse consecutive slashes. With libstdc++, a path containing tens of thousands of consecutive slash characters can recurse deeply enough to exhaust the stack and crash the process. `Router::route()`, `Router::addRoute()` and `Router::removeRoute()` reach this normalization. Unauthenticated remote exploitation is conditional on a deployment allowing sufficiently long request paths, such as by increasing `Endpoint::Options::maxRequestSize()` above the default 4096-byte limit or forwarding long paths through a front end. Direct router API use is also affected when attacker-controlled route or resource strings reach the normalizer. Native builds reproduced a crash around 24,000 consecutive slashes, although the exact threshold depends on the stack and standard library; the demonstrated failure is stack exhaustion rather than uninitialized-memory use. A source fix replaces recursive regular-expression normalization with an iterative pass, but no containing repository release was verified as of time of publication."}],"affected":[{"vendor":"pistacheio","product":"pistache","versions":[{"version":">= 0.0.5, <= 0.4.26","status":"affected"}]}],"references":[{"url":"https://github.com/pistacheio/pistache/security/advisories/GHSA-q474-pqcp-gqm5","name":"https://github.com/pistacheio/pistache/security/advisories/GHSA-q474-pqcp-gqm5","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/pistacheio/pistache/commit/935461352403696f3ca0dbb9a7de7d2609e7ce91","name":"https://github.com/pistacheio/pistache/commit/935461352403696f3ca0dbb9a7de7d2609e7ce91","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","lang":"en","description":"CWE-400: Uncontrolled Resource Consumption","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-674","lang":"en","description":"CWE-674: Uncontrolled Recursion","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-10-30T18:58:10.308Z"},"source":{"advisory":"GHSA-q474-pqcp-gqm5","discovery":"UNKNOWN"}}}}}