Python
CVE-2026-21428
HIGH
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Lifecycle Timeline
4DescriptionGitHub Advisory
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.
AnalysisAI
Cpp-Httplib versions up to 0.30.0 contains a vulnerability that allows attackers to add extra headers, modify request body unexpectedly & trigger an SSRF attack (CVSS 7.5).
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | cpp-httplib version prior to 0.30.0 used with HTTP/1.1 pipelining-enabled backend server (SpringBoot, Python Twisted, etc). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | CVSS 7.5 (HIGH). … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker could exploit this vulnerability to add extra headers, modify request body unexpectedly & trigger an SSRF attack. |
| Remediation | A vendor patch is available — apply it immediately. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 7 days: Identify all affected systems and apply vendor patches promptly. …
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Vendor StatusVendor
SUSE
Severity: High| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
| SUSE Linux Enterprise Server 16.0 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Fixed |
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