How severe is CVE-2025-53629?

CVE-2025-53629 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-53629 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-53629?

CVE-2025-53629 affects Yhirose Cpp-httplib. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-53629?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-53629 have an EU (EUVD) identifier?

Yes. CVE-2025-53629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21055.

When was CVE-2025-53629 published?

CVE-2025-53629 was published on 2025-07-10 and last updated on 2026-06-17.

CVE-2025-53629

CVE-2025-53629 is a high-severity vulnerability in Yhirose Cpp-httplib with a CVSS 3.x base score of 7.5. 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-21055
Weakness: CWE-770
Affected product: Yhirose Cpp-httplib
Published: 2025-07-10
Last modified: 2026-06-17

Description

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using Transfer-Encoding: chunked in the header can allocate memory arbitrarily in the server, potentially leading to its exhaustion. This vulnerability is fixed in 0.23.0. NOTE: This vulnerability is related to CVE-2025-53628.

Frequently asked questions

What is CVE-2025-53629?: cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using Transfer-Encoding: chunked in the header can allocate memory arbitrarily in the server, potentially leading to its exhaustion. This vulnerability is fixed in 0.23.0. NOTE: This vulnerability is related to CVE-2025-53628.
How severe is CVE-2025-53629?: CVE-2025-53629 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-53629 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-53629?: CVE-2025-53629 affects Yhirose Cpp-httplib. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-53629?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-53629 have an EU (EUVD) identifier?: Yes. CVE-2025-53629 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21055.
When was CVE-2025-53629 published?: CVE-2025-53629 was published on 2025-07-10 and last updated on 2026-06-17.

References

Affected products (1)

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

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CVE-2025-66570 — Critical (CVSS 10.0): cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability…
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CVE-2025-53628 — High (CVSS 8.8): cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not…
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