# CVE-2026-57159: PJSIP out-of-bounds read/write in SDP negotiator

Source: https://junglewise.ai/threats/cve-2026-57159-pjsip-out-of-bounds-read-write-in-sdp-negotiator  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-04. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-57159 · Severity: high · CVSS 7.5 · Published 2026-09-04

PJSIP is a multimedia communication library used in voice and video applications. When a non-default interoperability feature is enabled, the library fails to properly validate payload-type numbers in remote SDP offers, allowing an attacker to trigger out-of-bounds memory access. This can cause memory corruption and service denial, affecting applications that depend on PJSIP for real-time communications.

Technologies: [PJSIP Pjproject](https://junglewise.ai/threats/technologies/pjproject), [Teluu Pjsip](https://junglewise.ai/threats/technologies/pjsip). Vendors: [PJSIP](https://junglewise.ai/threats/vendors/pjsip), [Teluu](https://junglewise.ai/threats/vendors/teluu).

## Quick answers

**Is CVE-2026-57159 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-57159 being exploited in the wild.

**How severe is CVE-2026-57159?** High severity, with a CVSS score of 7.5, published 4 September 2026.

**Which products and versions are affected?** PJSIP Pjproject <= 2.17.

**Is there a fix for CVE-2026-57159?** A patch was published on 2026-09-04: patch available as commit 673b978 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-57159 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-57159?** Check whether you run PJSIP Pjproject or Teluu Pjsip at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds read/write (CWE-129, CWE-787) in the assign_pt_and_update_map() function within pjmedia/src/pjmedia/sdp_neg.c. The function parses payload-type numbers from remote SDP attributes (a=rtpmap, a=fmtp, RED references, and media format lists) and uses these untrusted values to index fixed-size arrays covering only payload types 96–127, without sufficient bounds validation. A crafted remote SDP with out-of-range payload numbers (e.g., "a=rtpmap:65535") causes memory access outside intended table boundaries. The attack requires no authentication and is network-accessible; it is only triggered when the PJMEDIA_SDP_NEG_MAINTAIN_REMOTE_PT_MAP compile-time feature is explicitly enabled (disabled by default). The practical impact is memory corruption and denial of service; code execution is not demonstrated. A fix is available in commit 673b978, which adds bounds checking via an is_dynamic_pt() helper.

## Affected products

- PJSIP pjproject <= 2.17

## Timeline

- 2026-06-17: disclosed
- 2026-09-04: patched: patch available as commit 673b978

## References

- [https://github.com/pjsip/pjproject/commit/673b978aab1fe3ab874247be32c871acc880cbeb](https://github.com/pjsip/pjproject/commit/673b978aab1fe3ab874247be32c871acc880cbeb)
- [https://github.com/pjsip/pjproject/security/advisories/GHSA-rfwg-w9gq-9mw2](https://github.com/pjsip/pjproject/security/advisories/GHSA-rfwg-w9gq-9mw2)

## Related threats

- [PJSIP stack buffer overflow in telnet CLI](https://junglewise.ai/threats/cve-2026-57166-pjsip-stack-buffer-overflow-in-telnet-cli)
- [PJSIP stack buffer overflow in telnet CLI history redraw](https://junglewise.ai/threats/cve-2026-57165-pjsip-stack-buffer-overflow-in-telnet-cli-history-redraw)
- [PJSIP heap buffer overflow in HTTP client](https://junglewise.ai/threats/cve-2026-57164-pjsip-heap-buffer-overflow-in-http-client)
- [PJSIP stack buffer overflow in GnuTLS TLS backend](https://junglewise.ai/threats/cve-2026-57163-pjsip-stack-buffer-overflow-in-gnutls-tls-backend)
- [PJSIP stack buffer overflow in SRTP/SDES SDP processing](https://junglewise.ai/threats/cve-2026-57162-pjsip-stack-buffer-overflow-in-srtp-sdes-sdp-processing)