Upstream information

CVE-2026-21428 at MITRE

Description

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.

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having important severity.

CVSS v3 Scores
CVSS detail National Vulnerability Database SUSE
Base Score 7.5 8.7
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Attack Vector Network Network
Attack Complexity Low High
Privileges Required None None
User Interaction None None
Scope Unchanged Changed
Confidentiality Impact None High
Integrity Impact High High
Availability Impact None None
CVSSv3 Version 3.1 3.1
CVSS v4 Scores
CVSS detail CNA (GitHub)
Base Score 7.7
Vector CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/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
Attack Vector Network
Attack Complexity Low
Attack Requirements None
Privileges Required None
User Interaction None
Vulnerable System Confidentiality Impact None
Vulnerable System Integrity Impact High
Vulnerable System Availability Impact None
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
CVSSv4 Version 4.0
SUSE Bugzilla entry: 1255835 [NEW]

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Server 16.0 cpp-httplib Affected
SUSE Linux Enterprise Server for SAP applications 16.0 cpp-httplib Affected
Products at an unknown state of their lifecycle.
SUSE Linux Enterprise Server for SAP Applications 16.0 cpp-httplib Affected


SUSE Timeline for this CVE

CVE page created: Thu Jan 1 20:00:08 2026
CVE page last modified: Thu Jan 8 20:44:00 2026