CVE-2021-43804

HIGHNVD 7.37.3—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.3 under NVD CVSS v3. EPSS exploit probability: 2.2%, top 19% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
7.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 2%CVSS: 7.3Exploit: NoneExposed: 0

A fix is available — apply it.

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In affected versions if the incoming RTCP BYE message contains a reason's length, this declared length is not checked against the actual received packet size, potentially resulting in an out-of-bound read access. This issue affects all users that use PJMEDIA and RTCP. A malicious actor can send a RTCP BYE message with an invalid reason length. Users are advised to upgrade as soon as possible. There are no known workarounds.

CVSS v3
7.3
EG Score
7.3(medium)
EG Risk
38(Track)
EG Risk 38/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity73% × 45%
Exploitation2% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
80.6%
KEV
Not listed

Published

December 22, 2021

Last Modified

November 4, 2025

References (15)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntujami-daemon (20230206.0~ds1-5ubuntu0.1) @ lunar2026-05-26ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 12× in last 7d / 46× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 105 total refreshes for this CVE.

  1. 2026-07-24 14:15 UTCEPSS rescore
  2. 2026-07-23 14:16 UTCEPSS rescore
  3. 2026-07-23 02:05 UTCEG score recompute
  4. 2026-07-22 22:51 UTCEG score recompute
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  1. 2026-07-07 13:43 UTCEPSS rescore
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  26. 2026-06-21 14:55 UTCEPSS rescore
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  44. 2026-06-12 14:10 UTCOSV refresh
  45. 2026-06-11 13:58 UTCEPSS rescore
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  47. 2026-06-10 22:16 UTCEPSS rescore
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Frequently asked(5)

What is CVE-2021-43804?
CVE-2021-43804 is a high vulnerability published on December 22, 2021. PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In affected versions if the incoming RTCP BYE message contains a reason's length, this declared length is not checked against the…
When was CVE-2021-43804 disclosed?
CVE-2021-43804 was first published in the National Vulnerability Database on December 22, 2021, with the most recent update on November 4, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-43804 actively exploited?
CVE-2021-43804 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 80.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-43804?
CVE-2021-43804 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2021-43804?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-43804, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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