NVD / CVE Program· CNA redhat

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

Noroxi assessment

Priority: Monitor (action score 14/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.22% (FIRST EPSS).
Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. Special conditions such as timing or configuration are required.
Fixed version: www.libssh.org/ libssh 0.11.2; azl3 libssh 0.10.6-2 on Azure Linux 3.0 0.10.6-3; azl3 libssh 0.10.6-3 on Azure Linux 3.0 0.10.6-3.

Low priority for now. Upgrade to www.libssh.org/ libssh 0.11.2; azl3 libssh 0.10.6-2 on Azure Linux 3.0 0.10.6-3; azl3 libssh 0.10.6-3 on Azure Linux 3.0 0.10.6-3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

LowCVSS 3.6 · v3.1—No exploit Fix available

Memory safety

Published: Jul 22, 2025
Updated: Sep 1, 2026
EPSS: 0.2% · 13th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 14 / 40 · 3.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · redhat: 3.6; NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

Red Hat Red Hat Enterprise Linux 10
- all versionsaffected
Red Hat Red Hat Enterprise Linux 6
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- all versionsaffected
Red Hat Red Hat Enterprise Linux 9
- 0:0.10.4-18.el9 and laternot affected · rpm
- 0:0.10.4-18.el9 and laternot affected · rpm
Red Hat Red Hat OpenShift Container Platform 4
- all versionsaffected
- all versionsaffected
www.libssh.org/ libssh
- before 0.11.2affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
AlmaLinux:9	libssh	before 0.10.4-18.el9	0.10.4-18.el9
AlmaLinux:9	libssh-config	before 0.10.4-18.el9	0.10.4-18.el9
AlmaLinux:9	libssh-devel	before 0.10.4-18.el9	0.10.4-18.el9
Debian:11	libssh	before 0.9.8-0+deb11u2	0.9.8-0+deb11u2
Debian:12	libssh	before 0.10.6-0+deb12u2	0.10.6-0+deb12u2
Debian:13	libssh	before 0.11.2-1	0.11.2-1
openSUSE:Leap 15.6	libssh	before 0.9.8-150600.11.3.1	0.9.8-150600.11.3.1
openSUSE:Tumbleweed	libssh	before 0.11.2-1.1	0.11.2-1.1
Red Hat:enterprise_linux:9::appstream	libssh-debuginfo	before 0:0.10.4-18.el9	0:0.10.4-18.el9
Red Hat:enterprise_linux:9::appstream	libssh-debugsource	before 0:0.10.4-18.el9	0:0.10.4-18.el9
Red Hat:enterprise_linux:9::appstream	libssh-devel	before 0:0.10.4-18.el9	0:0.10.4-18.el9
Red Hat:enterprise_linux:9::baseos	libssh	before 0:0.10.4-18.el9	0:0.10.4-18.el9
Red Hat:enterprise_linux:9::baseos	libssh-config	before 0:0.10.4-18.el9	0:0.10.4-18.el9
Rocky Linux:9	libssh	before 0:0.10.4-18.el9	0:0.10.4-18.el9
SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS	libssh	before 0.9.8-150200.13.9.1	0.9.8-150200.13.9.1
SUSE:Linux Enterprise Micro 5.3	libssh	before 0.9.8-150400.3.9.1	0.9.8-150400.3.9.1
SUSE:Linux Enterprise Module for Basesystem 15 SP6	libssh	before 0.9.8-150600.11.3.1	0.9.8-150600.11.3.1
SUSE:Linux Enterprise Server 12 SP5-LTSS	libssh	before 0.9.8-3.15.1	0.9.8-3.15.1
SUSE:Linux Enterprise Server 12 SP5-LTSS	libssh	before 0.6.3-12.15.1	0.6.3-12.15.1
SUSE:Linux Micro 6.0	libssh	before 0.10.6-2.1	0.10.6-2.1
SUSE:Linux Micro 6.1	libssh	before 0.10.6-slfo.1.1_2.1	0.10.6-slfo.1.1_2.1

Same product

red hat: all records

Other highest-scoring records for the same primary product.

CVE-2024-6409Openssh: possible remote code execution due to a race condition in signal handling affecting red hat enterprise linux 9
36Monitor
CVE-2026-75092Leapp-repository: leapp-upgrade-el9toel10: leapp-upgrade-el9toel10: scan_mysql runs mysqld --validate-config as root and can load mysql-writable plugins
29Monitor
CVE-2026-92925Redis: redis: out-of-bounds read via crafted cluster bus packets
28Monitor

Published before and after this one in the same product

← EarlierCVE-2024-45783Feb 18, 2025 · Grub2: fs/hfs+: refcount can be decremented twice
17Monitor
← EarlierCVE-2025-0690Feb 24, 2025 · Grub2: read: integer overflow may lead to out-of-bounds write
24Monitor
Later →CVE-2025-4877Aug 20, 2025 · Libssh: write beyond bounds in binary to base64 conversion functions
18Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
www.libssh.org/ libssh	0.11.2	Vendor (CNA)
azl3 libssh 0.10.6-2 on Azure Linux 3.0	0.10.6-3 · CBL-Mariner Releases	Microsoft (MSRC)
azl3 libssh 0.10.6-3 on Azure Linux 3.0	0.10.6-3 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 libssh 0.10.6-2 on CBL Mariner 2.0	0.10.6-3 · CBL-Mariner Releases	Microsoft (MSRC)
cbl2 libssh 0.10.6-3 on CBL Mariner 2.0	0.10.6-3 · CBL-Mariner Releases	Microsoft (MSRC)
almalinux:libssh	0.10.4-18.el9 · AlmaLinux:9	Package registry (OSV)
almalinux:libssh-config	0.10.4-18.el9 · AlmaLinux:9	Package registry (OSV)
almalinux:libssh-devel	0.10.4-18.el9 · AlmaLinux:9	Package registry (OSV)
debian:libssh	0.10.6-0+deb12u2 · Debian:12	Package registry (OSV)
opensuse:libssh	0.9.8-150600.11.3.1 · openSUSE:Leap 15.6	Package registry (OSV)
red hat:libssh	0:0.10.4-18.el9 · Red Hat:enterprise_linux:9::baseos	Package registry (OSV)
red hat:libssh-config	0:0.10.4-18.el9 · Red Hat:enterprise_linux:9::baseos	Package registry (OSV)
red hat:libssh-debuginfo	0:0.10.4-18.el9 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:libssh-debugsource	0:0.10.4-18.el9 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
red hat:libssh-devel	0:0.10.4-18.el9 · Red Hat:enterprise_linux:9::appstream	Package registry (OSV)
rocky linux:libssh	0:0.10.4-18.el9 · Rocky Linux:9	Package registry (OSV)
suse:libssh	0.9.8-150600.11.3.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP6	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

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Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone with local access to the system can trigger it.
A low-privileged account is enough.
No user action is required.
Special conditions such as timing or configuration are required.

If successful

Confidentiality: low · data can be read
Integrity: low · data or configuration can be modified
Availability: none

Attack vector: Local
Attack complexity: High
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: Low
Integrity impact: Low
Availability impact: None

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N

nvd-secondary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

Fix✗ → ✓Sep 28, 2026, 10:08 PM UTC

For records you follow, these changes also arrive as notifications. →

References

access.redhat.com/security/cve/CVE-2025-4878

Show all references (5 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records