EUVD-2026-71657Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/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
Network-reachable pre-auth overflow (PR:N, AV:N, AC:L); no confidentiality impact; integrity and availability both high from stack corruption or crash.
Primary rating from Vendor (GitHub_M).
CVSS VectorVendor: GitHub_M
Lifecycle Timeline
7DescriptionCVE.org
PJSIP is a free and open source multimedia communication library written in C. Prior to commit c4a151a, a stack buffer overflow exists in the GnuTLS TLS backend when parsing the Subject Alternative Name extension of a peer certificate (tls_cert_get_info() in ssl_sock_gtls.c). Only GnuTLS builds are affected (--with-gnutls); OpenSSL and Apple SecureTransport/Network.framework builds are not affected. While extracting certificate information after a TLS handshake, an incorrect buffer-size value can cause an oversized SubjectAltName entry to be written past the end of a fixed-size stack buffer. A network-positioned attacker presenting a crafted certificate - a malicious server to a connecting client, or a malicious client to a server that requests certificates - can trigger this during the TLS handshake, before any SIP-level authentication. Impact may range from unexpected application termination to control flow hijack/memory corruption. This issue has been patched via commit c4a151a.
AnalysisAI
Stack buffer overflow in PJSIP's GnuTLS TLS backend allows a network-positioned attacker to corrupt memory or hijack control flow by presenting a crafted X.509 certificate with an oversized Subject Alternative Name entry during TLS handshake. Only builds compiled with GnuTLS (--with-gnutls) are affected; OpenSSL and Apple SecureTransport/Network.framework builds are explicitly unaffected. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target PJSIP deployment was compiled with the --with-gnutls flag; OpenSSL and Apple SecureTransport builds are unaffected and constitute the majority of mainstream distributions. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:H) scores 8.8, reflecting network-reachable, pre-authentication exploitation with no complexity barrier. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upstream fix is available via commit c4a151af86fadd16d9480b2603eeb2abf4fb4f78; a released tagged version incorporating this fix has not been independently confirmed - operators should apply the patch from https://github.com/pjsip/pjproject/commit/c4a151af86fadd16d9480b2603eeb2abf4fb4f78 and rebuild. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all systems running PJSIP and determine which were compiled with the GnuTLS backend (--with-gnutls); OpenSSL and Apple SecureTransport builds are unaffected. …
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Same weakness CWE-121 – Stack-based Buffer Overflow
View allSame technique Buffer Overflow
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External POC / Exploit Code
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