Libssh: missing checks for return values for digests
A flaw was found in the libssh implements abstract layer for message digest (MD) operations implemented by different supported crypto backends. The return values from these were not properly checked, which could cause low-memory situations failures, NULL dereferences, crashes, or usage of the uninitialized memory as an input for the KDF. In this case, non-matching keys will result in decryption/integrity failures, terminating the connection.
- Published
- Dec 18, 2023
- Updated
- Jun 17, 2026
- EPSS
- 1.4% · 72th percentile
- CWE
- CWE-252
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Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.4%
CNA vs NVD score
- NVD
- 5.3
- CNA · redhat
- 3.7
- 1.6 point gap
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| libssh | libssh | cpe:2.3:a:libssh:libssh |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- fedoraproject fedora38
- fedoraproject fedora39
- libssh libssh0.9.0 and later · before 0.9.8
- libssh libssh0.10.0 and later · before 0.10.6
- redhat enterprise linux8.0
- redhat enterprise linux9.0
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 6
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- 0:0.9.6-14.el8 and laternot affected · rpm
- 0:0.9.6-14.el8 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9
- 0:0.10.4-13.el9 and laternot affected · rpm
- 0:0.10.4-13.el9 and laternot affected · rpm
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | libssh | before 0.9.6-14.el8 | 0.9.6-14.el8 |
| AlmaLinux:8 | libssh-config | before 0.9.6-14.el8 | 0.9.6-14.el8 |
| AlmaLinux:8 | libssh-devel | before 0.9.6-14.el8 | 0.9.6-14.el8 |
| AlmaLinux:9 | libssh | before 0.10.4-13.el9 | 0.10.4-13.el9 |
| AlmaLinux:9 | libssh-config | before 0.10.4-13.el9 | 0.10.4-13.el9 |
| AlmaLinux:9 | libssh-devel | before 0.10.4-13.el9 | 0.10.4-13.el9 |
| Debian:11 | libssh | before 0.9.8-0+deb11u1 | 0.9.8-0+deb11u1 |
| Debian:12 | libssh | before 0.10.6-0+deb12u1 | 0.10.6-0+deb12u1 |
| Debian:13 | libssh | before 0.10.6-1 | 0.10.6-1 |
| openSUSE:Tumbleweed | libssh | before 0.10.6-1.1 | 0.10.6-1.1 |
| Red Hat:enterprise_linux:8::appstream | libssh-debuginfo | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Red Hat:enterprise_linux:8::appstream | libssh-debugsource | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Red Hat:enterprise_linux:8::appstream | libssh-devel | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Red Hat:enterprise_linux:8::baseos | libssh | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Red Hat:enterprise_linux:8::baseos | libssh-config | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Red Hat:enterprise_linux:9::appstream | libssh-debuginfo | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| Red Hat:enterprise_linux:9::appstream | libssh-debugsource | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| Red Hat:enterprise_linux:9::appstream | libssh-devel | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| Red Hat:enterprise_linux:9::baseos | libssh | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| Red Hat:enterprise_linux:9::baseos | libssh-config | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| Rocky Linux:8 | libssh | before 0:0.9.6-14.el8 | 0:0.9.6-14.el8 |
| Rocky Linux:9 | libssh | before 0:0.10.4-13.el9 | 0:0.10.4-13.el9 |
| SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | libssh | before 0.9.8-150200.13.3.1 | 0.9.8-150200.13.3.1 |
| SUSE:Linux Enterprise Micro 5.3 | libssh | before 0.9.8-150400.3.3.1 | 0.9.8-150400.3.3.1 |
+2
Same product
libssh: all recordsOther highest-scoring records for the same primary product.
- CVE-2018-10933A vulnerability was found in libssh's server-side state machine before versions 0.7.6 and 0.8.4.64This week
- CVE-2019-14889A flaw was found with the libssh API function ssh_scp_new() in versions before 0.9.3 and before 0.8.8.36Monitor
- CVE-2026-59851Libssh: libssh: authentication bypass via missing gssapi principal check35Monitor
- CVE-2025-5372Libssh: incorrect return code handling in ssh_kdf() in libssh35Monitor
- CVE-2012-4562Multiple integer overflows in libssh before 0.5.3 allow remote attackers to cause a denial of service (infinite loop or crash) and possibly 34Monitor
- CVE-2026-0966Libssh: libssh: denial of service via zero-length input in ssh_get_hexa()32Monitor
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 |
|---|---|---|
| almalinux:libssh | 0.10.4-13.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libssh-config | 0.10.4-13.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libssh-devel | 0.10.4-13.el9 · AlmaLinux:9 | Package registry (OSV) |
| debian:libssh | 0.10.6-0+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:libssh | 0.9.8-150400.3.3.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| red hat:libssh | 0:0.10.4-13.el9 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:libssh-config | 0:0.10.4-13.el9 · Red Hat:enterprise_linux:9::baseos | Package registry (OSV) |
| red hat:libssh-debuginfo | 0:0.10.4-13.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libssh-debugsource | 0:0.10.4-13.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libssh-devel | 0:0.10.4-13.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| rocky linux:libssh | 0:0.10.4-13.el9 · Rocky Linux:9 | Package registry (OSV) |
| suse:libssh | 0.9.8-150400.3.3.1 · SUSE:Linux Enterprise Micro 5.3 | 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.
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.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- low · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- Low
Weakness class (CWE)
CWE-252 · Unchecked Return ValueCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
nvd-primary
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/security/cve/CVE-2023-6918
- access.redhat.com/errata/RHSA-2024:2504
- access.redhat.com/errata/RHSA-2024:3233
- bugzilla.redhat.com/show_bug.cgi?id=2254997
- www.libssh.org/2023/12/18/libssh-0-10-6-and-libssh-0-9-8-security-releases/
- www.libssh.org/security/advisories/CVE-2023-6918.txt
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LZQVUHWVWRH73YBXUQJOD6CKHDQBU3DM/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/MKQRBF3DWMWPH36LBCOBUTSIZRTPEZXB/
- security.netapp.com/advisory/ntap-20250214-0009/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.