How severe is CVE-2026-29076?

CVE-2026-29076 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-29076 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-29076?

CVE-2026-29076 affects Yhirose Cpp-httplib. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-29076?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-29076 have an EU (EUVD) identifier?

Yes. CVE-2026-29076 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10158.

When was CVE-2026-29076 published?

CVE-2026-29076 was published on 2026-03-07 and last updated on 2026-06-17.

CVE-2026-29076

CVE-2026-29076 is a medium-severity vulnerability in Yhirose Cpp-httplib with a CVSS 3.x base score of 5.9. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-674.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-10158
Weakness: CWE-674
Affected product: Yhirose Cpp-httplib
Published: 2026-03-07
Last modified: 2026-06-17

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. The regex engine in libstdc++ implements backtracking via deep recursion, consuming one stack frame per input character. An attacker can send a single HTTP POST request with a crafted filename* parameter that causes uncontrolled stack growth, resulting in a stack overflow (SIGSEGV) that crashes the server process. This issue has been patched in version 0.37.0.

Frequently asked questions

What is CVE-2026-29076?: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. The regex engine in libstdc++ implements backtracking via deep recursion, consuming one stack frame per input character. An attacker can send a single HTTP POST request with a crafted filename* parameter that causes uncontrolled stack growth, resulting in a stack overflow (SIGSEGV) that crashes the server process. This issue has been patched in version 0.37.0.
How severe is CVE-2026-29076?: CVE-2026-29076 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-29076 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-29076?: CVE-2026-29076 affects Yhirose Cpp-httplib. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-29076?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-29076 have an EU (EUVD) identifier?: Yes. CVE-2026-29076 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-10158.
When was CVE-2026-29076 published?: CVE-2026-29076 was published on 2026-03-07 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*

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