CVE-2026-40892 PJSIP: Stack buffer overflow in pjsip_auth_create_digest2()

What is CVE-2026-40892?

CVE-2026-40892 is a high-severity memory corruption vulnerability in pjsip pjproject, published on 21 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

PJSIP is a free and open source multimedia communication library written in C. In 2.16 and earlier, a stack buffer overflow exists in pjsip_auth_create_digest2() in PJSIP when using pre-computed digest credentials (PJSIP_CRED_DATA_DIGEST). The function copies credential data using cred_info->data.slen as the length without an upper-bound check, which can overflow the fixed-size ha1 stack buffer (128 bytes) if data.slen exceeds the expected digest string length.

Weakness: CWE-121

Which versions are affected by CVE-2026-40892?

It affects 1 product.

Products include Pjsip Pjsip.

How do I fix CVE-2026-40892?

Upgrade to a fixed version.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-40892 being exploited?

There is no known exploitation of CVE-2026-40892 in the wild and no public exploit code.

Other vulnerabilities in pjsip pjproject

• CVE-2026-28799 PJSIP: Heap use-after-free in PJSIP presence subscription termination handler High 8.7
• CVE-2026-29068 PJSIP: Stack buffer overflow in Opus codec parser High 8.7
• CVE-2026-40614 PJSIP: Heap buffer overflow in Opus codec decoding High 8.5
• CVE-2026-32945 PJSIP is vulnerable to Heap-based Buffer Overflow through DNS parser High 8.4
• CVE-2026-26967 PJSIP has a Heap-based Buffer Overflow vulnerability in its H.264 unpacketizer High 8.1

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as ALPINE-CVE-2026-40892, DEBIAN-CVE-2026-40892, GHSA-2wcg-w3c4-48r7, UBUNTU-CVE-2026-40892.