CVE-2025-53629
cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability
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.
- Record
CVE-2025-53629- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2025-21055
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.
- Record
EUVD-2025-21055- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-53629- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
OSV
cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability
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.
- Record
CVE-2025-53629- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-770
- Updated
- 2026-11-02
OSVDEBIAN-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.
- Record
DEBIAN-CVE-2025-53629- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVOESA-2025-1839
cpp-httplib security update
A C++11 single-file header-only cross platform HTTP/HTTPS library. It's extremely easy to setup. Just include httplib.h file in your code!
Security Fix(es):
CPP-HTTPLIB is a C++11 single file header that only cross-platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using transfer code: blocks in the title can arbitrarily allocate memory in the server, which may cause it to be exhausted. The vulnerability is fixed in 0.23.0. Note: This vulnerability is related to CVE-2025-53628.(CVE-2025-53629)
- Record
OESA-2025-1839- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
Show 7 moreShow less
OSVOESA-2025-1840
cpp-httplib security update
A C++11 single-file header-only cross platform HTTP/HTTPS library. It's extremely easy to setup. Just include httplib.h file in your code!
Security Fix(es):
CPP-HTTPLIB is a C++11 single file header that only cross-platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using transfer code: blocks in the title can arbitrarily allocate memory in the server, which may cause it to be exhausted. The vulnerability is fixed in 0.23.0. Note: This vulnerability is related to CVE-2025-53628.(CVE-2025-53629)
- Record
OESA-2025-1840- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVOESA-2025-1841
cpp-httplib security update
A C++11 single-file header-only cross platform HTTP/HTTPS library. It's extremely easy to setup. Just include httplib.h file in your code!
Security Fix(es):
CPP-HTTPLIB is a C++11 single file header that only cross-platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using transfer code: blocks in the title can arbitrarily allocate memory in the server, which may cause it to be exhausted. The vulnerability is fixed in 0.23.0. Note: This vulnerability is related to CVE-2025-53628.(CVE-2025-53629)
- Record
OESA-2025-1841- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVOESA-2025-1842
cpp-httplib security update
A C++11 single-file header-only cross platform HTTP/HTTPS library. It's extremely easy to setup. Just include httplib.h file in your code!
Security Fix(es):
CPP-HTTPLIB is a C++11 single file header that only cross-platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using transfer code: blocks in the title can arbitrarily allocate memory in the server, which may cause it to be exhausted. The vulnerability is fixed in 0.23.0. Note: This vulnerability is related to CVE-2025-53628.(CVE-2025-53629)
- Record
OESA-2025-1842- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVOESA-2025-1843
cpp-httplib security update
A C++11 single-file header-only cross platform HTTP/HTTPS library. It's extremely easy to setup. Just include httplib.h file in your code!
Security Fix(es):
CPP-HTTPLIB is a C++11 single file header that only cross-platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using transfer code: blocks in the title can arbitrarily allocate memory in the server, which may cause it to be exhausted. The vulnerability is fixed in 0.23.0. Note: This vulnerability is related to CVE-2025-53628.(CVE-2025-53629)
- Record
OESA-2025-1843- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-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.
- Record
UBUNTU-CVE-2025-53629- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:20295-1 No score
Security update for cpp-httplib
This update for cpp-httplib fixes the following issues:
- CVE-2025-53629: header can allocate memory arbitrarily in the server, potentially leading to its exhaustion (bsc#1246471).
- CVE-2025-53628: HTTP header smuggling due to insecure trailers merge (bsc#1246468).
- Record
openSUSE-SU-2026:20295-1- Updated
- 2026-11-02
OSVSUSE-SU-2026:20600-1 No score
Security update for cpp-httplib
This update for cpp-httplib fixes the following issues:
- CVE-2025-53629: header can allocate memory arbitrarily in the server, potentially leading to its exhaustion (bsc#1246471).
- CVE-2025-53628: HTTP header smuggling due to insecure trailers merge (bsc#1246468).
- Record
SUSE-SU-2026:20600-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
cpp-httplibDebian:12 |
All versions, plus listed versions 0.11.4+ds-10.11.4+ds-1+deb12u10.11.4+ds-20.11.4+ds-30.13.1+ds-1 Show 22 moreShow less0.14.0+ds-10.14.1+ds-10.14.1+ds-20.14.2+ds-10.14.3+ds-10.14.3+ds-1.10.14.3+ds-1.1~exp10.15.3+ds-10.15.3+ds-20.15.3+ds-30.16.0+ds-10.16.3+ds-10.16.3+ds-20.18.0+ds-10.18.7-10.20.1+ds-30.25.0+ds-10.26.0+ds-20.41.0+ds-10.41.0+ds-20.41.0+ds-30.41.0+ds-3~bpo13+1 |
None known |
cpp-httplibDebian:13 |
before 0.18.7-1+deb13u1, plus listed versions 0.18.7-1 |
0.18.7-1+deb13u1 |
cpp-httplibDebian:14 |
before 0.25.0+ds-3, plus listed versions 0.18.7-10.20.1+ds-30.25.0+ds-1 |
0.25.0+ds-3 |
cpp-httplibopenEuler:24.03-LTS-SP1 |
before 0.22.0-2.oe2403sp1 | 0.22.0-2.oe2403sp1 |
cpp-httplibopenEuler:24.03-LTS-SP2 |
before 0.22.0-2.oe2403sp2 | 0.22.0-2.oe2403sp2 |
cpp-httplibopenEuler:22.03-LTS-SP3 |
before 0.22.0-2.oe2203sp3 | 0.22.0-2.oe2203sp3 |
cpp-httplibopenEuler:22.03-LTS-SP4 |
before 0.22.0-2.oe2203sp4 | 0.22.0-2.oe2203sp4 |
cpp-httplibopenEuler:24.03-LTS |
before 0.22.0-2.oe2403 | 0.22.0-2.oe2403 |
cpp-httplibSUSE:Linux Enterprise Server 16.0 From an advisory covering 2 CVEs |
before 0.22.0-160000.4.1 | 0.22.0-160000.4.1 |
cpp-httplibSUSE:Linux Enterprise Server for SAP applications 16.0 From an advisory covering 2 CVEs |
before 0.22.0-160000.4.1 | 0.22.0-160000.4.1 |
Show 5 moreShow less
| Package | Affected | Fixed |
|---|---|---|
cpp-httplibUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 0.9.9+ds-10.9.10+ds-10.10.1+ds-10.10.2+ds-10.10.3+ds-10.10.3+ds-1ubuntu0.1~esm10.10.3+ds-1ubuntu0.1~esm2 |
None known |
cpp-httplibUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 0.13.1+ds-1ubuntu10.14.3+ds-10.14.3+ds-1.10.14.3+ds-1.1build10.14.3+ds-1.1build20.14.3+ds-1.1ubuntu0.1~esm10.14.3+ds-1.1ubuntu0.1~esm2 |
None known |
cpp-httplibUbuntu:25.10 |
All versions, plus listed versions 0.18.7-10.18.7-1ubuntu0.25.10.10.18.7-1ubuntu0.25.10.2 |
None known |
cpp-httplibUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 0.18.7-10.26.0+ds-2ubuntu20.26.0+ds-2ubuntu30.26.0+ds-2ubuntu3+esm1 |
None known |
cpp-httplibopenSUSE:Leap 16.0 From an advisory covering 2 CVEs |
before 0.22.0-160000.4.1 | 0.22.0-160000.4.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-53629 is a high vulnerability (CVSS 7.5) in Yhirose Cpp-httplib, published July 10, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.59%, the 48th percentile. Fixed in cpp-httplib 0.18.7-1+deb13u1.
References
github.com/yhirose/cpp-httplib/security/advisories/GHSA-qjmq-h3cc-qv6w
nvd.nist.gov/vuln/detail/CVE-2025-53629
security-tracker.debian.org/tracker/CVE-2025-53629
Show 12 moreShow less
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2025-1839
suse.com/support/update/announcement/2026/suse-su-202620600-1
bugzilla.suse.com/1246468
ubuntu.com/security/CVE-2025-53629
cve.org/CVERecord?id=CVE-2025-53629