CVE-2026-58051: libssh2 Use of Uninitialized Resource
Vulnerability summary
CVE-2026-58051 is a high (CVSS 8.3) Use of Uninitialized Resource vulnerability in libssh2. EPSS estimates a 0.28% chance of exploitation in the next 30 days, higher than 18.8% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 15 · Related 13Timeline
- 28-06-2026PublishedVulnerability first disclosed.
- 29-06-2026Last modifiedVulnerability information updated.
Description
libssh2 through 1.11.1 grows its publickey list with SSH2_REALLOC but does not zero-initialize new entries before parsing populates them, so a parse failure reaching the cleanup path leaves libssh2_publickey_list_free operating on an uninitialized entry. A malicious SSH server offering the publickey subsystem can use a malformed response to make cleanup free an uninitialized, attacker-influenceable attrs pointer in a connecting libssh2 client.
CVSS metrics
11 scores · 8 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- OSV · DebianEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · WolfiEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N
- NVDNIST8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · AlpineEcosystem advisory · calculated8.3HighCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- OSV · Red hatEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS trend
Probability
0.28%
Chance of exploitation in the next 30 days
Percentile
19%
Versus all other CVEs
30-day change
0.00 pp
From 0.28% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploitarium
Maturity: poc
Weaknesses
CWE · root causeAffected systems
Chainguard3 products
- libssh2All versions (No fix recorded)
- libssh2-devAll versions (No fix recorded)
- libssh2-docAll versions (No fix recorded)
Redhat3 products
- libssh2< 0:1.11.1-10.1.hum1
- libssh2-devel< 0:1.11.1-10.1.hum1
- libssh2-docs< 0:1.11.1-10.1.hum1
Wolfi3 products
- libssh2All versions (No fix recorded)
- libssh2-devAll versions (No fix recorded)
- libssh2-docAll versions (No fix recorded)
Alpine1 product
- libssh2< 1.11.1-r4
Debian1 product
- libssh2< 1.10.0-3+deb12u1 | < 1.11.1-1+deb13u2 | < 1.11.1-6
Libssh21 product
- libssh2≤ 1.11.1
Ubuntu1 product
- libssh2< 1.4.3-2ubuntu0.2+esm4 | < 1.5.0-2ubuntu0.1+esm3 | < 1.8.0-1ubuntu0.1+esm1 | < 1.8.0-2.1ubuntu0.1+esm1 | < 1.10.0-3ubuntu0.1 | < 1.11.0-4.1ubuntu0.24.04.3 | All versions (No fix recorded) | < 1.11.1-1ubuntu0.26.04.3
7 vendors · 13 products
References
18 links- github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-pocExploitThird Party AdvisoryARTICLEREPORTEVIDENCEBroken Link
- www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanupThird Party AdvisoryARTICLEREPORTAdvisory
- images.redhat.comARTICLE
