CVE-2026-58050: libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response

Q: How do I fix CVE-2026-58050?

libssh2: upgrade to newer than 1.11.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-58050 being exploited?

CVE-2026-58050 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-2026-58050 affect?

CVE-2026-58050 affects libssh2. Severity is high (CVSS 7.0). libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the

Q: How urgent is CVE-2026-58050?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.0REMOTEUPGRADE

CVE-2026-58050 is a high-severity flaw (CVSS 7.0) affecting libssh2. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.0 (High)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-190
Published	2026-06-28
Last modified	2026-10-25

Publisher (CNA): VulnCheck · Vendor: libssh2

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-28 02:16 UTCPublished CVE record published
2026-10-25 17:10 UTCUpdated Record last modified

libssh2 libssh2 UPGRADE

Affected: <= 1.11.1

Fixed in: newer than 1.11.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libssh2 || rpm -q libssh2 || libssh2 --version

2. UPGRADE to newer than 1.11.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libssh2

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libssh2

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-2026-58050?

libssh2: upgrade to newer than 1.11.1. Exact commands for each OS are on this page.

Is CVE-2026-58050 being exploited?

CVE-2026-58050 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-2026-58050 affect?

CVE-2026-58050 affects libssh2. Severity is high (CVSS 7.0). libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the

How urgent is CVE-2026-58050?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-58051 MEDIUM 6.5 UPGRADE libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries bef
CVE-2026-55200 HIGH 8.1 DOWNGRADE libssh2 1.11.1, fixed in commit 97acf3d, contains an out-of-bounds write vulnerability in ssh2_transport_read(

References

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