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NVD / CVE Program· CNA GitHub_M

CVE-2021-43845: Prevent out-of-bounds read in PJSIP

Noroxi assessment

Priority: Monitor (action score 37/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 3.8% (FIRST EPSS); higher than 90.1% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: pjproject (Alpine:v3.16) 2.12-r0; asterisk (Debian:10) 1:16.28.0~dfsg-0+deb10u1; ring (Debian:10) 20190215.1.f152c98~ds1-1+deb10u2.

Low priority for now. Upgrade to pjproject (Alpine:v3.16) 2.12-r0; asterisk (Debian:10) 1:16.28.0~dfsg-0+deb10u1; ring (Debian:10) 20190215.1.f152c98~ds1-1+deb10u2 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

PJSIP is a free and open source multimedia communication library. In version 2.11.1 and prior, if incoming RTCP XR message contain block, the data field is not checked against the received packet size, potentially resulting in an out-of-bound read access. This affects all users that use PJMEDIA and RTCP XR. A malicious actor can send a RTCP XR message with an invalid packet size.

CriticalCVSS 9.1 · v3.1—No exploit Fix available
Published
Dec 27, 2021
Updated
Jun 17, 2026
EPSS
3.8% · 90th percentile

Report tools

JSON

Action score

37

Monitor

Low priority for now.

CVSS
36 / 40 · 9.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
1 / 30 · 3.8%

CNA vs NVD score

NVD
9.1
CNA · GitHub_M
8.2
0.9 point gap

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-43845

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
teluupjsip
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux10.0
  • debian debian linux11.0
  • debian debian linux9.0
  • teluu pjsipup to 2.11.1 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (GitHub_M). Independent of NVD's CPE analysis and usually ahead of it.

  • pjsip pjproject

    • <= 2.11.1affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.16pjprojectbefore 2.12-r02.12-r0
Debian:10asteriskbefore 1:16.28.0~dfsg-0+deb10u11:16.28.0~dfsg-0+deb10u1
Debian:10ringbefore 20190215.1.f152c98~ds1-1+deb10u220190215.1.f152c98~ds1-1+deb10u2
Debian:11asteriskbefore 1:16.28.0~dfsg-0+deb11u11:16.28.0~dfsg-0+deb11u1
Debian:11ringbefore 20210112.2.b757bac~ds1-1+deb11u120210112.2.b757bac~ds1-1+deb11u1
Debian:12ringbefore 20230206.0~ds1-120230206.0~ds1-1
Debian:14asteriskbefore 1:18.12.0~dfsg+~cs6.12.40431413-11:18.12.0~dfsg+~cs6.12.40431413-1
Debian:9pjprojectbefore 2.5.5~dfsg-6+deb9u32.5.5~dfsg-6+deb9u3

Same product

teluu: all records

Other highest-scoring records for the same primary product.

Published before and after this one in the same product

  • ← EarlierCVE-2021-37706Dec 22, 2021 · Potential integer underflow upon receiving STUN message in PJSIP
    40Plan
  • ← EarlierCVE-2021-43804Dec 22, 2021 · Out-of-bounds read when parsing RTCP BYE message in PJSIP
    30Monitor
  • Later →CVE-2021-41141Jan 4, 2022 · Missing release of locks in PJSIP
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:pjproject2.12-r0 · Alpine:v3.16Package registry (OSV)
debian:asterisk1:18.12.0~dfsg+~cs6.12.40431413-1 · Debian:14Package registry (OSV)
debian:pjproject2.5.5~dfsg-6+deb9u3 · Debian:9Package registry (OSV)
debian:ring20230206.0~ds1-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-125 · Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records