5.8

CVE-2026-73213: Coturn: `addr_less_eq()` does a component-wise IPv6 comparison instead of a lexicographic one, letting an authenticated TURN client bypass `denied-peer-ip`/`allowed-peer-ip` IPv6 ranges (TURN-specific SSRF)

Deferred
AliasesUBUNTU-CVE-2026-73213DEBIAN-CVE-2026-73213
Published 11-08-2026Last modified 13-08-2026

Vulnerability summary

CVE-2026-73213 is a medium (CVSS 5.8) Incorrect Authorization vulnerability in coturn. EPSS estimates a 0.41% chance of exploitation in the next 30 days, higher than 34.5% of scored vulnerabilities.

Overall risk
23/100
0100
Low · default modelHow is this calculated?
CVSS score
5.8/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.41%
0%100%
Low · +0.03 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 1 · Related 1
OPENSUSE-SU-2026:11617-1

Timeline

  1. 11-08-2026
    PublishedVulnerability first disclosed.
  2. 13-08-2026
    Last modifiedVulnerability information updated.

Description

Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.16.0, addr_less_eq() in src/client/ns_turn_ioaddr.c uses a component-wise comparison for native IPv6 min-max intervals in ioa_addr_in_range(), allowing an authenticated TURN client to relay to an IPv6 peer that is numerically within a configured non-prefix-aligned denied-peer-ip range but is classified as outside it. This issue is fixed in version 4.16.0.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.41%

Chance of exploitation in the next 30 days

Percentile

35%

Versus all other CVEs

30-day change

Increase +0.03 pp

From 0.39% on 22-09-2026

22-09-202622-10-2026

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

Coturn1 product
Debian1 product
  • coturnAll versions (No fix recorded) | < 4.18.0-1
Ubuntu1 product
  • coturnAll versions (No fix recorded)

3 vendors · 3 products

References

6 links