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CVE-2026-59842

LOW 3.7

Published 2026-07-21 · Last modified 2026-08-19

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.

NO EXPLOITATION SIGNALS

No known exploitation, public exploit, or elevated probability at this time. Track for changes.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 36th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

3.7CVSS 3.1 · LOW

  • ConfidentialityLow
  • IntegrityNone
  • AvailabilityNone

What an attacker needs

  • Access: Reachable over the network — no local access needed
  • Privileges: No account or privileges required
  • User interaction: No user interaction needed
  • Complexity: Needs a race window or specific setup

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-59842/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-59842/poc.json

Affected

Vendors Red Hat Libssh Redhat

Products Red Hat Enterprise Linux 10 Red Hat Hardened Images Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Libssh Hardened Images Enterprise Linux

Weakness (CWE)

  • CWE-125: Out-of-bounds Read

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

Known Affected Software Configurations

VendorProductVersion range
LibsshLibssh*
RedhatHardened Images*
RedhatEnterprise Linux10.0

All CVSS metrics

  • LOW 3.7 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
  • LOW 3.7 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
  • MEDIUM 5.3 v3.1 · NVD Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

Advisories

Sources: NVD · CVE.org · EPSS