Libssh: write beyond bounds in binary to base64 conversion functions
There's a vulnerability in the libssh package where when a libssh consumer passes in an unexpectedly large input buffer to ssh_get_fingerprint_hash() function. In such cases the bin_to_base64() function can experience an integer overflow leading to a memory under allocation, when that happens it's possible that the program perform out of bounds write leading to a heap corruption. This issue affects only 32-bits builds of libssh.
- Published
- Aug 20, 2025
- Updated
- Aug 31, 2026
- EPSS
- 0.2% · 8th percentile
- CWE
- CWE-787
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Report tools
Action score
18
Monitor
Low priority for now.
- CVSS
- 18 / 40 · 4.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · redhat
- 4.5
- 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.
Affected systems
—
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 versionsunknown
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 versionsunknown
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 versionsunknown
- all versionsunknown
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: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 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 recordsOther 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 936Monitor
- CVE-2026-75092Leapp-repository: leapp-upgrade-el9toel10: leapp-upgrade-el9toel10: scan_mysql runs mysqld --validate-config as root and can load mysql-writable plugins29Monitor
- CVE-2026-42169Gimp: gimp apng loader heap-buffer-overflow when fctl width exceeds ihdr width (file-png.c)29Monitor
- CVE-2026-58379Gimp: gimp: heap buffer overflow in read_channel_data()29Monitor
- CVE-2026-92925Redis: redis: out-of-bounds read via crafted cluster bus packets28Monitor
- CVE-2024-45774Grub2: reader/jpeg: heap oob write during jpeg parsing26Monitor
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) |
| 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, 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.
- CVE-2024-45774183 days apartGrub2: reader/jpeg: heap oob write during jpeg parsing26Monitor
- CVE-2025-0690177 days apartGrub2: read: integer overflow may lead to out-of-bounds write24Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
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
- low · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- Low
- Integrity impact
- Low
- Availability impact
- Low
Weakness class (CWE)
CWE-787 · Out-of-bounds WriteCVSS vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
nvd-secondary
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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- access.redhat.com/errata/RHSA-2026:18683
- access.redhat.com/security/cve/CVE-2025-4877
- bugzilla.redhat.com/show_bug.cgi?id=2376193
- git.libssh.org/projects/libssh.git/commit/?h=stable-0.11&id=6fd9cc8ce3958092a1aae11f1f2e911b2747732d
- www.libssh.org/security/advisories/CVE-2025-4877.txt
Vendor advisories and official records. Exploit/PoC links are deliberately left out.