CVE-2026-59843 (GCVE-0-2026-59843)

Vulnerability from cvelistv5 – Published: 2026-07-21 11:16 – Updated: 2026-09-01 20:01
VLAI
Title
Libssh: libssh: denial of service via zero advertised channel packet size
Summary
A flaw was found in libssh. A remote authenticated peer can advertise a zero maximum packet size in SSH_MSG_CHANNEL_OPEN, causing later channel writes to loop indefinitely and consume CPU, leading to denial of service.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-21 12:08 UTC
CWE
  • CWE-835 - Loop with Unreachable Exit Condition ('Infinite Loop')
  • CWE-400 - Uncontrolled Resource Consumption
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:42922 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:55855 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:62217 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:62218 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-59843 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2498176 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat Enterprise Linux 10 Unaffected: 0:0.12.0-3.el10_2 , < * (rpm)
    cpe:/o:redhat:enterprise_linux:10.2
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 8 Unaffected: 0:0.9.6-17.el8_10 , < * (rpm)
    cpe:/a:redhat:enterprise_linux:8::appstream
    cpe:/o:redhat:enterprise_linux:8::baseos
Create a notification for this product.
Red Hat Red Hat Enterprise Linux 9 Unaffected: 0:0.10.4-19.el9_8 , < * (rpm)
    cpe:/a:redhat:enterprise_linux:9::appstream
    cpe:/o:redhat:enterprise_linux:9::baseos
Create a notification for this product.
Red Hat Red Hat Hardened Images Unaffected: 0.12.1-4.hum1 , < * (rpm)
    cpe:/a:redhat:hummingbird:1
Create a notification for this product.
Date Public
2026-07-21 11:07
Show details on NVD website

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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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Detection rules are retrieved from Rulezet.

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Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.


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