{"id":"CVE-2026-62303","title":"Pistache: DoS via stack exhaustion in REST router path normalization (regex_replace on long slash runs)","summary":"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.…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-400","CWE-674"],"vendor":"pistacheio","product":"pistache","affected":["pistache >= 0.0.5, <= 0.4.26"],"published":"2026-10-30","updated":"2026-10-30","sourceUpdated":"2026-10-30T18:58:10.308Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-62303","references":[{"url":"https://github.com/pistacheio/pistache/security/advisories/GHSA-q474-pqcp-gqm5","label":"https://github.com/pistacheio/pistache/security/advisories/GHSA-q474-pqcp-gqm5"},{"url":"https://github.com/pistacheio/pistache/commit/935461352403696f3ca0dbb9a7de7d2609e7ce91","label":"https://github.com/pistacheio/pistache/commit/935461352403696f3ca0dbb9a7de7d2609e7ce91"}],"tags":["cve.org"],"epss":0.00308,"epssPercentile":0.23821,"ingestedAt":"2026-11-05T16:24:31.396Z","slug":"CVE-2026-62303","body":"## Overview\n\nPistache 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.\n\n## Affected\n\n- `pistache >= 0.0.5, <= 0.4.26`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}