CVE-2026-35387: OpenSSH before 10.3 can use unintended ECDSA algorithms

Q: How do I fix CVE-2026-35387?

openssh: upgrade to 10.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-35387 being exploited?

CVE-2026-35387 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-35387 affect?

CVE-2026-35387 affects openssh. Severity is low (CVSS 3.1). OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.

Q: How urgent is CVE-2026-35387?

Priority 20/100. On your watchlist

Routine

LOW 3.1WATCHLISTUPGRADE

CVE-2026-35387 is a low-severity flaw (CVSS 3.1) affecting openssh. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	3.1 (Low)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-670
Published	2026-04-02
Last modified	2026-07-24

Publisher (CNA): MITRE · Vendor: openbsd

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-02 17:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

openbsd openssh UPGRADE

Affected: < 10.3

Fixed in: 10.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openssh || rpm -q openssh || openssh --version

2. UPGRADE to 10.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openssh

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openssh

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-35387?

openssh: upgrade to 10.3. Exact commands for each OS are on this page.

Is CVE-2026-35387 being exploited?

CVE-2026-35387 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-35387 affect?

CVE-2026-35387 affects openssh. Severity is low (CVSS 3.1). OpenSSH before 10.3 can use unintended ECDSA algorithms. Listing of any ECDSA algorithm in PubkeyAcceptedAlgorithms or HostbasedAcceptedAlgorithms is misinterpreted to mean all ECDSA algorithms.

How urgent is CVE-2026-35387?

Priority 20/100. On your watchlist

Software pages

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References

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