5.3

CVE-2026-116566: socket.getaddrinfo() accepts embedded null bytes in host and port

Awaiting analysis
AliasesDEBIAN-CVE-2026-116566
Published 29-10-2026Last modified 30-10-2026

Vulnerability summary

CVE-2026-116566 is a medium (CVSS 5.3) vulnerability in python software foundation cpython. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, adjacent network); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.26%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 29-10-2026
    PublishedVulnerability first disclosed.
  2. 30-10-2026
    Last modifiedVulnerability information updated.

Description

socket.getaddrinfo() previously accepted null bytes within *host* and *port* parameters which can cause the values to be silently truncated.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

18%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

30-10-202603-11-2026

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: adjacent network, administrative account, user interaction (CVSS vector). Other conditions: not stated in public data.

Debian4 products
  • python3.11All versions (No fix recorded)
  • python3.13All versions (No fix recorded)
  • python3.14All versions (No fix recorded)
  • python3.15All versions (No fix recorded)
Python software foundation1 product

2 vendors · 5 products

References

6 links