CVE Explorer
CVE-2026-21428
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 si
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"cpp-httplib","vendor":"yhirose","versions":[{"status":"affected","version":"< 0.30.0"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":7.7,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"HIGH"},"metric_type":"cvssV4_0"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/metrics/0/cvssV4_0
CWE assertions
1 source assertion{"cweId":"CWE-93","description":"CWE-93: Improper Neutralization of CRLF Sequences ('CRLF Injection')","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/problemTypes/0/descriptions/0
Source references
3 source assertions{"name":"https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd","tags":["x_refsource_MISC"],"url":"https://github.com/yhirose/cpp-httplib/commit/98048a033a532ff22320ce1d11789f8d5710dfcd"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/references/1
{"name":"https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0","tags":["x_refsource_MISC"],"url":"https://github.com/yhirose/cpp-httplib/releases/tag/v0.30.0"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/references/2
{"name":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7","tags":["x_refsource_CONFIRM"],"url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-wpc6-j37r-jcx7"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:3cee1a215568755f50d6ffa2c91693dbc50925314e6b49d4351141a0cf784f64 · sha256:10dd10b2c8273799… · /containers/cna/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.