pistacheio Pistache up to 0.4.26 Router Normalization src/server/router.cc sanitizeResource stack-based overflow

Summaryinfo

A vulnerability, which was classified as problematic, has been found in pistacheio Pistache up to 0.4.26. This impacts the function SegmentTreeNode::sanitizeResource of the file src/server/router.cc of the component Router Normalization. Performing a manipulation results in stack-based overflow. This vulnerability is cataloged as CVE-2026-62303. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, was found in pistacheio Pistache up to 0.4.26. This affects the function SegmentTreeNode::sanitizeResource of the file src/server/router.cc of the component Router Normalization. The manipulation with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-62303 since 07/13/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 10/30/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-114262). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Vendor

• pistacheio

Name

• Pistache

Version

• 0.4.0
• 0.4.1
• 0.4.2
• 0.4.3
• 0.4.4
• 0.4.5
• 0.4.6
• 0.4.7
• 0.4.8
• 0.4.9
• 0.4.10
• 0.4.11
• 0.4.12
• 0.4.13
• 0.4.14
• 0.4.15
• 0.4.16
• 0.4.17
• 0.4.18
• 0.4.19
• 0.4.20
• 0.4.21
• 0.4.22
• 0.4.23
• 0.4.24
• 0.4.25
• 0.4.26

Website

• Product: https://github.com/pistacheio/pistache/

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