Unrated

Heap Use-After-Free in Asterisk PJSIP TCP/SDP Handling

IdentifiersCVE-2026-57187CWE-416

CVE-2026-57187 is a heap use-after-free vulnerability in Asterisk's PJSIP handling of TCP/SDP state when a connection-oriented SIP session is closed during SDP processing. According to the advisory, an authenticated attacker can trigger the flaw by sending a SIP INVITE over a connection-oriented transport such as TCP and then disconnecting before Asterisk sends its 200 OK response. This can result in dereferencing freed heap memory during the lifetime management of resources associated with SDP processing. The issue is mapped to CWE-416 and also associated with improper resource lifetime control. The advisory notes that the crash has only been reproducible when Asterisk is built with Address Sanitizer enabled.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can crash the Asterisk process, causing a denial-of-service condition and loss of availability. The published CVSS v4 vector indicates impact is limited to availability, with no demonstrated confidentiality or integrity impact. Based on the provided information, the practical effect described is service disruption rather than code execution.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure of authenticated SIP access over connection-oriented transports used by PJSIP, especially TCP-based signaling paths reachable by untrusted or low-trust users. Limit which authenticated endpoints can send SIP INVITE requests, restrict network access to trusted peers, and monitor for abnormal disconnect patterns during call setup. However, the primary mitigation is to apply the vendor patch. The advisory also notes the issue has only been reproducible with Address Sanitizer-enabled builds, which are typically development builds rather than production deployments.

Remediation

Patch, then assume compromise.

Upgrade Asterisk to a patched release. The advisory states fixes are available in Asterisk 20.20.1, 21.12.3, 22.10.1, and 23.4.1, and in certified-Asterisk 20.7-cert11 and 22.8-cert3. Affected versions include Asterisk 20.20.0 and earlier, 21.12.2 and earlier, 22.10.0 and earlier, 23.4.0 and earlier, plus certified-Asterisk 20.7-cert10 and earlier and 22.8-cert2 and earlier.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

2 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

2 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1