A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment… (CVE-2026-59846)
A vulnerability in libssh allows a malicious username expanded through %r in ProxyCommand handling to inject shell metacharacters. This can expose environment variables and cause unintended shell behavior. The issue has been assigned CVE-2026-59846 and is rated as low severity. Red Hat has released updates for libssh in their Hardened Images RPMs to address this flaw.
AI Analysis
Technical Summary
CVE-2026-59846 is a vulnerability in libssh where a maliciously crafted username, when expanded via the %r placeholder in ProxyCommand handling, can inject shell metacharacters. This injection can lead to exposure of environment variables and unintended shell command execution behavior. The vulnerability has a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N, indicating local attack vector with low impact on confidentiality and integrity, and no availability impact. Red Hat has issued a security advisory with updated libssh packages (libssh-0.12.1-4.hum1) to remediate this issue in their Hardened Images RPMs.
Potential Impact
The vulnerability allows local attackers with limited privileges to inject shell metacharacters via a malicious username in ProxyCommand handling, potentially exposing environment variables and causing unintended shell behavior. The impact is limited to confidentiality and integrity with no availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
Red Hat has released updated libssh packages as part of their Hardened Images RPMs (libssh-0.12.1-4.hum1) that fix this vulnerability. Users of affected Red Hat Hardened Images should apply these updates promptly. Patch status is confirmed by the vendor advisory. No additional mitigation steps are indicated by the vendor.
A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment… (CVE-2026-59846)
Description
A vulnerability in libssh allows a malicious username expanded through %r in ProxyCommand handling to inject shell metacharacters. This can expose environment variables and cause unintended shell behavior. The issue has been assigned CVE-2026-59846 and is rated as low severity. Red Hat has released updates for libssh in their Hardened Images RPMs to address this flaw.
CVSS v3.1
Score 3.9low
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-59846 is a vulnerability in libssh where a maliciously crafted username, when expanded via the %r placeholder in ProxyCommand handling, can inject shell metacharacters. This injection can lead to exposure of environment variables and unintended shell command execution behavior. The vulnerability has a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:N, indicating local attack vector with low impact on confidentiality and integrity, and no availability impact. Red Hat has issued a security advisory with updated libssh packages (libssh-0.12.1-4.hum1) to remediate this issue in their Hardened Images RPMs.
Potential Impact
The vulnerability allows local attackers with limited privileges to inject shell metacharacters via a malicious username in ProxyCommand handling, potentially exposing environment variables and causing unintended shell behavior. The impact is limited to confidentiality and integrity with no availability impact. There are no known exploits in the wild at this time.
Mitigation Recommendations
Red Hat has released updated libssh packages as part of their Hardened Images RPMs (libssh-0.12.1-4.hum1) that fix this vulnerability. Users of affected Red Hat Hardened Images should apply these updates promptly. Patch status is confirmed by the vendor advisory. No additional mitigation steps are indicated by the vendor.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-fvwj-j79q-57v7
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-59846"]
- Ecosystems
- []
- Database Specific Severity
- LOW
- Cvss Version
- 3.1
Threat ID: 6a6150e19c2644c7f8da17c5
Added to database: 07/22/2026, 23:23:13 UTC
Last enriched: 07/22/2026, 23:35:34 UTC
Last updated: 07/31/2026, 19:24:47 UTC
Views: 38
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