CVE-2026-35388

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

Published: 2026-04-02 Last update: 2026-04-27 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2026-35388 is rated Low Risk (10.5/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.01%). Mandatory action: Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-35388

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-03 0.01%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-35388

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.5 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
1.0 1.4 [email protected]
2.5 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
1.0 1.4 [email protected]

Weakness enumeration for CVE-2026-35388

OS Trackers for CVE-2026-35388

vendor priority summary link
debian not yet assigned CVE-2026-35388 not yet assigned priority: Debian including 1 source packages (openssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-35388
redhat low https://access.redhat.com/security/cve/CVE-2026-35388
suse low CVE-2026-35388 severity low: SUSE including 4 source package names (openssh, openssh-cavs, openssh-fips, openssh-helpers), 8 product×package rows across 3 product lines (SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE, SUSE Linux Enterprise Server 12 SP4-LTSS, SUSE Linux Enterprise Server Teradata 12 SP3): Known Not Affected 8. https://www.suse.com/security/cve/CVE-2026-35388/
ubuntu medium CVE-2026-35388 medium priority: Ubuntu including 2 source packages (openssh, openssh-ssh1), 16 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): ignored 7, needs-triage 5, released 4. https://ubuntu.com/security/CVE-2026-35388

Affected software / configurations for CVE-2026-35388

Vendor Product Version Raw CPE
openbsd openssh < 10.3 cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*

References for CVE-2026-35388

cvelogic Threat Intelligence