7.5

CVE-2026-49847: FreeSWITCH: Stack overflow in bundled cJSON parser via deeply nested JSON

Analyzed
Published 09-06-2026Last modified 09-06-2026

Vulnerability summary

CVE-2026-49847 is a high (CVSS 7.5) Uncontrolled Recursion vulnerability in freeswitch. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 36% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 10-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (CVE.org)
EPSS score
0.41%
0%100%
Low · -0.12 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 09-06-2026
    PublishedVulnerability first disclosed.
  2. 09-06-2026
    Last modifiedVulnerability information updated.

Description

FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to version 1.11.1, a single unauthenticated WebSocket frame containing a deeply nested JSON document crashes the FreeSWITCH process via stack overflow, terminating all calls and sessions on the host. The recursion drives the worker thread's stack pointer into the stack guard page, raising SIGSEGV from the kernel before any usable write primitive develops. This issue has been patched in version 1.11.1.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

36%

Versus all other CVEs

30-day change

Decrease -0.12 pp

From 0.53% on 11-10-2026

11-10-202610-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Freeswitch1 product
Signalwire1 product

2 vendors · 2 products

References

2 links