Security readout for executives and security teams
Plain-English summary
CVE-2021-43845 is a memory-read flaw in PJSIP pjproject. Systems using PJMEDIA with RTCP XR can be affected when processing a malformed incoming RTCP XR packet. The cited CVSS is high because exploitation is network reachable, needs no credentials or user action, and may expose memory or cause limited availability impact.
Executive priority
Prioritize remediation for internet-facing or partner-facing voice and real-time communications services. The risk is high because the flaw is remotely reachable without authentication, but the provided sources do not show known active exploitation. Patch through vendor-supported updates and verify bundled dependencies.
Technical view
pjproject 2.11.1 and earlier do not adequately validate an RTCP XR block data field against the received packet size, creating an out-of-bounds read in PJMEDIA RTCP XR handling. The public sources identify CWE-125, CVSS 8.2, and a fix in the upstream pull request and commit.
Likely exposure
Exposure is most likely in VoIP, SIP, conferencing, softphone, PBX, or embedded communications products that bundle or link pjproject <= 2.11.1 and enable PJMEDIA RTCP XR. Downstream Debian and Gentoo advisories show packaged ecosystem impact, including pjproject-related consumers.
Exploitation context
The source bundle says a malicious actor can send an RTCP XR message with an invalid packet size. It does not cite public exploitation in the wild, and KEV status is false. Treat this as remotely reachable where affected RTCP XR processing is exposed, but do not assume active exploitation from the provided evidence.
Researcher notes
Focus validation on RTCP XR parsing in PJMEDIA and version provenance. The key boundary is whether the RTCP XR block length is checked against the received packet size. Evidence supports upstream remediation through PR #2924 and commit f74c1fc22b760d2a24369aa72c74c4a9ab985859.
Mitigation direction
- Upgrade pjproject or vendor packages to a release containing the upstream fix.
- Prioritize systems using PJMEDIA with RTCP XR over generic pjproject deployments.
- Apply Debian, Gentoo, or other distributor security updates where applicable.
- Check vendor guidance for products bundling pjproject rather than patching blindly.
- Retire or isolate unsupported products that remain on pjproject <= 2.11.1.
Validation and detection
- Inventory applications and appliances using PJSIP, PJMEDIA, pjproject, Asterisk, or Ring packages.
- Confirm whether deployed pjproject versions are <= 2.11.1.
- Verify whether PJMEDIA RTCP XR support is enabled or reachable.
- Confirm installed packages include the relevant distributor security update.
- Review SBOMs and vendor notices for statically bundled pjproject copies.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-43845 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L3.94.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/pjsip/pjproject/security/advisories/GHSA-r374-qrwv-86hhCVE reference
- https://github.com/pjsip/pjproject/pull/2924CVE reference
- https://github.com/pjsip/pjproject/commit/f74c1fc22b760d2a24369aa72c74c4a9ab985859CVE reference
- [debian-lts-announce] 20220328 [SECURITY] [DLA 2962-1] pjproject security updateCVE reference · mailing-list
- GLSA-202210-37CVE reference · vendor-advisory
- [debian-lts-announce] 20221117 [SECURITY] [DLA 3194-1] asterisk security updateCVE reference · mailing-list
- DSA-5285CVE reference · vendor-advisory
- [debian-lts-announce] 20230829 [SECURITY] [DLA 3549-1] ring security updateCVE reference · mailing-list
- https://lists.debian.org/debian-lts-announce/2024/09/msg00030.htmlCVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.