CVE-2025-4878 | Libssh: use of uninitialized variable in privatekey_from_file()

A vulnerability was found in libssh, where an uninitialized variable exists under certain conditions in the privatekey_from_file() function. This flaw can be triggered if the file specified by the filename doesn't exist and may lead to possible signing failures or heap corruption.

Published: 2025-07-22 Last update: 2026-05-19 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2025-4878 is rated Low Risk (29.3/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.20%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2025-4878

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 2026-05-22 0.10% 0.20% +0.10%
2 2026-05-18 0.01% 0.10% +0.09%
3 2025-07-23 — 0.01% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-4878

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.6 3.1 LOW
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
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 2.5 [email protected]

Weakness enumeration for CVE-2025-4878

GitHub Security Advisory for CVE-2025-4878

GHSA-q2fw-m52x-w593 · Severity: low — A vulnerability was found in libssh, where an uninitialized variable exists under certain...

OS Trackers for CVE-2025-4878

vendor priority summary link
alpine — CVE-2025-4878: 1 source package rows (libssh); 2 state rows across 2 repos (3.22-community, edge-community); fixed 2, open 0. https://security.alpinelinux.org/vuln/CVE-2025-4878
debian not yet assigned CVE-2025-4878 not yet assigned priority: Debian including 1 source packages (libssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2025-4878
redhat low — https://access.redhat.com/security/cve/CVE-2025-4878
suse medium CVE-2025-4878 severity moderate: SUSE including 352 source package names (0.0.17-1.1:libssh-config-0.9.8-150600.11.3.1, 0.0.17-1.1:libssh4-0.9.8-150600.11.3.1, …), 1051 product×package rows across 364 product lines (Container bci/kiwi, Container bci/spack, … (364 product lines)): Fixed 830, Known Affected 221. https://www.suse.com/security/cve/CVE-2025-4878/
ubuntu medium CVE-2025-4878 medium priority: Ubuntu including 1 source packages (libssh), 8 status rows across 8 suites (bionic, focal, jammy, noble, oracular, plucky, upstream, xenial): released 8. https://ubuntu.com/security/CVE-2025-4878

Affected software / configurations for CVE-2025-4878

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-4878

cvelogic Threat Intelligence