CVE-2025-53628
cpp-httplib does not limit the length of a line
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
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
- Low
- Integrity
- Low
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
cpp-httplib does not limit the length of a line
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
CVE-2025-53628- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-835, CWE-770
- Updated
- 2026-11-02
EUVDEUVD-2025-21053
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
EUVD-2025-21053- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N - Updated
- 2026-11-02
NVD
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
CVE-2025-53628- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-770, CWE-835, CWE-444
- Updated
- 2026-11-02
OSV
cpp-httplib does not limit the length of a line
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
CVE-2025-53628- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N - Weakness
- CWE-770, CWE-835
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2025-53628
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
DEBIAN-CVE-2025-53628- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-53628
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
- Record
UBUNTU-CVE-2025-53628- CVSS 4.0
- 6.3 Medium
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N - CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-04
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 |
All versions, plus listed versions 0.18.7-10.18.7-1+deb13u10.20.1+ds-30.25.0+ds-10.26.0+ds-2 Show 4 moreShow less0.41.0+ds-10.41.0+ds-20.41.0+ds-30.41.0+ds-3~bpo13+1 |
None known |
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-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 |
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-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 | ||
| affected, facts | OSV | |
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-53628 is a medium vulnerability (CVSS 6.3) 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 0.52%, the 44th percentile. Fixed in cpp-httplib 0.25.0+ds-3.
References
github.com/yhirose/cpp-httplib/security/advisories/GHSA-j6p8-779x-p5pw
nvd.nist.gov/vuln/detail/CVE-2025-53628
security-tracker.debian.org/tracker/CVE-2025-53628