CVE-2021-43303Network attack vector

Memory corruption via undersized call-dump output buffer

Published Feb 16, 2022 · Updated Nov 4, 2025

Buffer overflow in Teluu PJSIP 2.11.1 and earlier allows attackers to corrupt memory through a short PJSUA call-dump output buffer. The pjsua_call_dump function copies a generated call report with pj_ansi_strcpy without honoring maxlen, then appends line-ending bytes. Exploitation requires a consuming application to supply attacker-controlled output storage smaller than 128 bytes, producing an out-of-bounds write.

CVSS severity9.8
Critical
EPSS probability2.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Teluu PJSIP 2.11.1 and earlier allows attackers to corrupt memory through a short PJSUA call-dump output buffer. The pjsua_call_dump function copies a generated call report with pj_ansi_strcpy without honoring maxlen, then appends line-ending bytes. Exploitation requires a consuming application to supply attacker-controlled output storage smaller than 128 bytes, producing an out-of-bounds write.

The record

CVE
CVE-2021-43303
Published
Feb 16, 2022
Updated
Nov 4, 2025
Vendor
Teluu
Product
PJSIP
Classifications
CWE-120
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=unspecified <=2.11.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Teluu · PJSIPversion=unspecified <=2.11.1

Published CVSS scores

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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