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CVE-2026-22776

cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb

8.7 HighFix available

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

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

0.41%Up 0.4 points since Jan 13, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.7

cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
CVE-2026-22776
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-409
Updated
2026-11-02
EUVDEUVD-2026-2006 8.7

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
EUVD-2026-2006
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-02
NVD 8.7

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
CVE-2026-22776
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-409
Updated
2026-11-02
OSV 8.7

cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
CVE-2026-22776
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-409
Updated
2026-11-02
OSVDEBIAN-CVE-2026-22776 7.5

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
DEBIAN-CVE-2026-22776
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVOESA-2026-1158 8.7

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-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the write_headers function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.(CVE-2026-21428)

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory. An attacker can exploit this by sending a compressed payload with a very high compression ratio (e.g., a zip bomb), which upon decompression consumes excessive memory, leading to service unavailability.(CVE-2026-22776)

Record
OESA-2026-1158
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
Updated
2026-11-02
Show 7 moreShow less
OSVOESA-2026-1159 8.7

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-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the write_headers function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.(CVE-2026-21428)

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory. An attacker can exploit this by sending a compressed payload with a very high compression ratio (e.g., a zip bomb), which upon decompression consumes excessive memory, leading to service unavailability.(CVE-2026-22776)

Record
OESA-2026-1159
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
Updated
2026-11-02
OSVOESA-2026-1160 8.7

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-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the write_headers function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.(CVE-2026-21428)

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory. An attacker can exploit this by sending a compressed payload with a very high compression ratio (e.g., a zip bomb), which upon decompression consumes excessive memory, leading to service unavailability.(CVE-2026-22776)

Record
OESA-2026-1160
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
Updated
2026-11-02
OSVOESA-2026-1161 8.7

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-only cross platform HTTP/HTTPS library. Prior to version 0.30.0, the write_headers function does not check for CR & LF characters in user supplied headers, allowing untrusted header value to escape header lines. This vulnerability allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack. When combined with a server that supports http1.1 pipelining (springboot, python twisted etc), this can be used for server side request forgery (SSRF). Version 0.30.0 fixes this issue.(CVE-2026-21428)

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory. An attacker can exploit this by sending a compressed payload with a very high compression ratio (e.g., a zip bomb), which upon decompression consumes excessive memory, leading to service unavailability.(CVE-2026-22776)

Record
OESA-2026-1161
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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
Updated
2026-11-02
OSVUBUNTU-CVE-2026-22776 8.7

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Record
UBUNTU-CVE-2026-22776
CVSS 4.0
8.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2026:10435-1 No score

cpp-httplib-devel-0.38.0-1.1 on GA media

These are all security issues fixed in the cpp-httplib-devel-0.38.0-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:10435-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:20733-1 No score

Security update for cpp-httplib

This update for cpp-httplib fixes the following issues

  • CVE-2026-21428: server-side request forgery via header injection (bsc#1255835).
  • CVE-2026-22776: unsafe handling of compressed HTTP request can cause a denial of service (bsc#1256518).
  • CVE-2026-28434: default exception handler may leak e.what() to clients via EXCEPTION_WHAT response header (bsc#1259221).
  • CVE-2026-28435: payload size limit bypass via gzip decompression in ContentReader (streaming) can lead to denial of service (bsc#1259220).
  • CVE-2026-29076: denial of service via crafted HTTP POST request (bsc#1259373).
Record
openSUSE-SU-2026:20733-1
Updated
2026-11-02
OSVSUSE-SU-2026:21599-1 No score

Security update for cpp-httplib

This update for cpp-httplib fixes the following issues

  • CVE-2026-21428: server-side request forgery via header injection (bsc#1255835).
  • CVE-2026-22776: unsafe handling of compressed HTTP request can cause a denial of service (bsc#1256518).
  • CVE-2026-28434: default exception handler may leak e.what() to clients via EXCEPTION_WHAT response header (bsc#1259221).
  • CVE-2026-28435: payload size limit bypass via gzip decompression in ContentReader (streaming) can lead to denial of service (bsc#1259220).
  • CVE-2026-29076: denial of service via crafted HTTP POST request (bsc#1259373).
Record
SUSE-SU-2026:21599-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
cpp-httplib
Debian: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 less
0.14.0+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-httplib
Debian: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 less
0.41.0+ds-10.41.0+ds-20.41.0+ds-30.41.0+ds-3~bpo13+1
 None known
cpp-httplib
Debian:14
 before 0.41.0+ds-3, plus listed versions
0.18.7-10.20.1+ds-30.25.0+ds-10.26.0+ds-20.41.0+ds-10.41.0+ds-20.41.0+ds-3~bpo13+1
0.41.0+ds-3
cpp-httplib
openEuler:24.03-LTS
From an advisory covering 2 CVEs
 before 0.30.1-1.oe2403
0.30.1-1.oe2403
cpp-httplib
openEuler:24.03-LTS-SP1
From an advisory covering 2 CVEs
 before 0.30.1-1.oe2403sp1
0.30.1-1.oe2403sp1
cpp-httplib
openEuler:24.03-LTS-SP2
From an advisory covering 2 CVEs
 before 0.30.1-1.oe2403sp2
0.30.1-1.oe2403sp2
cpp-httplib
openEuler:24.03-LTS-SP3
From an advisory covering 2 CVEs
 before 0.30.1-1.oe2403sp3
0.30.1-1.oe2403sp3
cpp-httplib
Ubuntu: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-httplib
Ubuntu: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-httplib
Ubuntu: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-httplib
Ubuntu:26.10
 All versions, plus listed versions
0.26.0+ds-2ubuntu30.26.0+ds-2ubuntu4
 None known
cpp-httplib
Ubuntu: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-httplib
openSUSE:Tumbleweed
From an advisory covering 6 CVEs
 before 0.38.0-1.1
0.38.0-1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-22776 is a high vulnerability (CVSS 8.7) in Yhirose Cpp-httplib, published January 12, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.41%, the 35th percentile. Fixed in cpp-httplib 0.41.0+ds-3.

References

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