2.5

CVE-2026-35388: openbsd openssh Unprotected Alternate Channel

CVSS: 2.5v3.1LowAnalyzed
AliasesUBUNTU-CVE-2026-35388DEBIAN-CVE-2026-35388
Published 02-04-2026Last modified 02-04-2026
Open JSON

Vulnerability summary

CVE-2026-35388 is a low (CVSS 2.5) Unprotected Alternate Channel vulnerability in openbsd openssh. EPSS estimates a 0.23% chance of exploitation in the next 30 days, higher than 12.6% of scored vulnerabilities.

Overall risk
10/100
0100
Low · default modelHow is this calculated?
CVSS score
2.5/10
010
Low · v3.1 (CVE.org)
EPSS score
0.23%
0%100%
Low · +0.10 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 22 · Related 10
MGASA-2026-0193OPENSUSE-SU-2026:10937-1OPENSUSE-SU-2026:21044-1RHSA-2026:12389RHSA-2026:13380RHSA-2026:13381

Timeline

  1. 02-04-2026
    PublishedVulnerability first disclosed.
  2. 02-04-2026
    Last modifiedVulnerability information updated.

Description

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.23%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

+0.10 pp

From 0.13% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.23%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu2 products
  • opensshAll versions (No fix recorded) | < 1:8.9p1-3ubuntu0.15 | < 1:8.9p1-3ubuntu0.15+Fips1 | < 1:9.6p1-3ubuntu13.16 | < 1:9.6p1-3ubuntu13.16+Fips1 | < 1:10.0p1-5ubuntu5.4 | < 1:10.2p1-2ubuntu3.2
  • openssh-ssh1All versions (No fix recorded)
Debian1 product
  • openssh< 1:9.2p1-2+deb12u10 | < 1:10.0p1-7+deb13u3 | < 1:10.3p1-1
Openbsd1 product

3 vendors · 4 products

References

8 links