NVD / CVE Program· CNA GitHub_M

CVE-2026-28799: PJSIP: Heap use-after-free in PJSIP presence subscription termination handler

Noroxi assessment

Priority: Monitor (action score 34/100)

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: 0.32% (FIRST EPSS).
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.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: pjsip pjproject 2.17.

Low priority for now. Upgrade to pjsip pjproject 2.17 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 written in C. Prior to version 2.17, a heap use-after-free vulnerability exists in PJSIP's event subscription framework (evsub.c) that is triggered during presence unsubscription (SUBSCRIBE with Expires=0). This issue has been patched in version 2.17.

HighCVSS 8.7 · v4.0—No exploit Fix available

Published: Mar 6, 2026
Updated: Jun 17, 2026
EPSS: 0.3% · 25th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 34 / 40 · 8.7 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.3%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 8.7; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

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.

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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.

Vendor	Product	CPE
pjsip	pjsip	cpe:2.3:a:pjsip:pjsip

Affected versions

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

pjsip pjsipbefore 2.17

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
- < 2.17affected

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Alpine:v3.24	pjproject	before 2.17-r0	2.17-r0
Debian:14	asterisk	before 1:22.10.0+dfsg+~cs6.17.60671434-1	1:22.10.0+dfsg+~cs6.17.60671434-1

Same product

pjsip: all records

Other highest-scoring records for the same primary product.

CVE-2022-24786Potential out-of-bound read/write in PJSIP
40Plan
CVE-2022-23547Heap buffer overflow in pjproject when decoding STUN message
39Monitor
CVE-2022-39244Buffer overflow in pjlib scanner and pjmedia
39Monitor

Published before and after this one in the same product

← EarlierCVE-2026-26203Feb 19, 2026 · PJSIP's pjmedia-video has use-after-free in H264 packetizer when packetizing fragmented NAL
20Monitor
← EarlierCVE-2026-26967Feb 19, 2026 · PJSIP has a Heap-based Buffer Overflow vulnerability in its H.264 unpacketizer
32Monitor
Later →CVE-2026-29068Mar 6, 2026 · PJSIP: Stack buffer overflow in Opus codec parser
34Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
pjsip pjproject	2.17 · description	Vendor (CNA)
alpine:pjproject	2.17-r0 · Alpine:v3.24	Package registry (OSV)
debian:asterisk	1:22.10.0+dfsg+~cs6.17.60671434-1 · Debian:14	Package 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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

pjsip/pjprojectcommit e06ff6c

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.

CVE-2026-3294214 days apartPJSIP has ICE session use-after-free race conditions
32Monitor
CVE-2026-2620315 days apartPJSIP's pjmedia-video has use-after-free in H264 packetizer when packetizing fragmented NAL
20Monitor

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
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: X

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:48 PM UTC

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

References

github.com/pjsip/pjproject/commit/e06ff6c64741cc1675fd3296615910f532f6b1a1

Show all references (1 more)

github.com/pjsip/pjproject/security/advisories/GHSA-8fj4-fv9f-hjpc

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

All records