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Fencer Vulns
high 7.5

CVE-2023-27598 json

OpenSIPS has vulnerability in the parse_via() function

published 2023-03-15 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-31337

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 62%
public exploits
0
none known

Summary

OpenSIPS is a Session Initiation Protocol (SIP) server implementation. Prior to versions 3.1.7 and 3.2.4, sending a malformed `Via` header to OpenSIPS triggers a segmentation fault when the function `calc_tag_suffix` is called. A specially crafted `Via` header, which is deemed correct by the parser, will pass uninitialized strings to the function `MD5StringArray` which leads to the crash. Abuse of this vulnerability leads to Denial of Service due to a crash. Since the uninitialized string points to memory location `0x0`, no further exploitation appears to be possible. No special network privileges are required to perform this attack, as long as the OpenSIPS configuration makes use of functions such as `sl_send_reply` or `sl_gen_totag` that trigger the vulnerable code. This issue has been fixed in versions 3.1.7 and 3.2.4.

Patch / fix

  • opensips opensips 3.1.7, 3.2.4

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
20 mo ago

Exploit prediction

0.97% chance of exploitation in the next 30 days, higher than 62% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • OpenSIPS opensips

Classification

Weakness
  • CWE-908 Use of Uninitialized Resource

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.