CVE-2026-59842: libssh Out-of-bounds Read
CVSS: 5.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-59842DEBIAN-CVE-2026-59842CGA-2hf9-8jgp-rjfmCGA-37jg-hxfv-32w9CGA-m3r4-j8g5-38v2CGA-qm3h-92fp-cmhhCGA-w2h3-7m3j-84h4CGA-xfc7-vpcp-r4wh
Published 21-07-2026Last modified 19-08-2026
Vulnerability summary
CVE-2026-59842 is a medium (CVSS 5.3) Out-of-bounds Read vulnerability in libssh. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 41% of scored vulnerabilities.
CVSS score
5.3/10
010
Medium · v3.1 (NVD)EPSS score
0.49%
0%100%
Low · +0.09 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Advisory lineage
Upstream 0 · Downstream 2 · Related 1Timeline
- 21-07-2026PublishedVulnerability first disclosed.
- 19-08-2026Last modifiedVulnerability information updated.
Description
A flaw was found in libssh. During server-side GSSAPI key exchange, a client-supplied Curve25519 public key shorter than the expected length is copied without proper length validation, leading to an out-of-bounds heap read. This could allow a remote unauthenticated attacker to disclose small amounts of server memory.
CVSS metrics
4 scores · 4 sources · 1 versionMedium 5.3Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NSources4 sources · 3.7–5.3
- CVE.orgCNA3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:NDiffers
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- OSV · DebianEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
EPSS trend
Probability
0.49%
Chance of exploitation in the next 30 days
Percentile
41%
Versus all other CVEs
30-day change
+0.09 pp
From 0.41% on 19-09-2026
19-09-202619-10-2026
EPSS score0.49%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Redhat10 products
- enterprise_linux10.0 | 10.2
- enterprise_linux_for_els10.2
- enterprise_linux_for_eus10.2
- enterprise_linux_for_ibm_z_systems10.0 | 10.2
- enterprise_linux_for_ibm_z_systems_els10.2
Chainguard3 products
- libssh< 0.12.1-r0
- libssh-dev< 0.12.1-r0
- libssh2All versions (No fix recorded)
Wolfi3 products
- libssh< 0.12.1-r0
- libssh-dev< 0.12.1-r0
- libssh2All versions (No fix recorded)
Debian1 product
- libssh< 0.12.1-1
Libssh1 product
- libssh0.12.0
Ubuntu1 product
- libsshAll versions (No fix recorded)
6 vendors · 19 products
