CVE-2026-58051
libssh2 - Free of Uninitialized Pointer in publickey List Cleanup
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.
INFO
Published Date :
June 28, 2026, 2:16 a.m.
Last Modified :
Nov. 10, 2026, 1:19 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update libssh2 to a fixed version.
- Ensure all new entries are zero-initialized.
- Validate cleanup paths for memory safety.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-58051.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-58051 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-58051
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-58051 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-58051 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by [email protected]
Nov. 10, 2026
Action Type Old Value New Value Added Reference https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc Added Reference https://github.com/libssh2/libssh2/blob/master/src/publickey.c Added Reference https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup Removed Reference https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc Removed Reference https://github.com/libssh2/libssh2/blob/master/src/publickey.c Removed Reference https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup Removed Reference Type https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc Types: Broken Link Removed Reference Type https://github.com/libssh2/libssh2/blob/master/src/publickey.c Types: Product Removed Reference Type https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup Types: Third Party Advisory -
CVE Modified by 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
Nov. 10, 2026
Action Type Old Value New Value Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/58xxx/CVE-2026-58051.json">CVE-2026-58051</a> Added Reference https://cert-portal.siemens.com/productcert/html/ssa-457936.html -
CVE Translated by [email protected]
Oct. 25, 2026
Action Type Old Value New Value Added Translation Title: libssh2 - Free of Uninitialized Pointer in publickey List Cleanup, Description: libssh2 hasta la versión 1.11.1 aumenta su lista de claves públicas con SSH2_REALLOC pero no inicializa a cero las nuevas entradas antes de que el análisis las complete, por lo que un fallo de análisis que alcanza la ruta de limpieza deja a libssh2_publickey_list_free operando sobre una entrada no inicializada. Un servidor SSH malicioso que ofrece el subsistema publickey puede usar una respuesta malformada para hacer que la limpieza libere un puntero attrs no inicializado y que puede ser influenciado por el atacante en un cliente libssh2 que se conecta. -
Initial Analysis by [email protected]
Jun. 30, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:libssh2:libssh2:*:*:*:*:*:*:*:* versions up to (including) 1.11.1 Added Reference Type VulnCheck: https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc Types: Broken Link Added Reference Type VulnCheck: https://github.com/libssh2/libssh2/blob/master/src/publickey.c Types: Product Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup Types: Third Party Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 29, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-58051', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-29T12:49:30.651264Z'} -
New CVE Received by [email protected]
Jun. 28, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'libssh2', 'product': 'libssh2', 'versions': [{'status': 'affected', 'version': '0', 'versionType': 'semver', 'lessThanOrEqual': '1.11.1'}], 'defaultStatus': 'affected'}] Added 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H Added CWE CWE-908 Added Reference https://github.com/bikini/exploitarium/tree/main/libssh2-publickey-list-calc-poc Added Reference https://github.com/libssh2/libssh2/blob/master/src/publickey.c Added Reference https://www.vulncheck.com/advisories/libssh2-free-of-uninitialized-pointer-in-publickey-list-cleanup