Security readout for executives and security teams
Plain-English summary
CVE-2025-8277 is a low-severity libssh memory leak during SSH key exchange. Repeated bad key-exchange guesses can consume memory over time and may crash affected client-side applications, reducing availability. There is no provided evidence of active exploitation or KEV listing.
Executive priority
Treat as routine patch management, not an emergency, unless critical services rely heavily on affected libssh clients. Prioritize systems where client crashes would disrupt automation, operations, or customer-facing workflows.
Technical view
libssh does not free memory correctly during repeated rekey operations triggered by incorrect KEX guesses. The issue is CWE-401 with CVSS 3.1 score 3.1: network reachable, high complexity, low privileges required, no confidentiality or integrity impact, and low availability impact.
Likely exposure
Exposure is most relevant where applications use affected libssh packages in listed Red Hat products: RHEL 8, 9, 10, RHIVOS 1, OpenShift Container Platform 4 rhcos, and RHEL 7 libssh2 per the bundle. RHEL 6 libssh2 status is listed as unknown.
Exploitation context
Sources describe memory exhaustion through repeated incorrect KEX guesses during SSH rekeying. The reported impact is client-side crashes, especially with libgcrypt. The CVSS vector indicates network access, high attack complexity, low privileges, no user interaction, and limited availability impact.
Researcher notes
No KEV listing is provided, and the bundle does not show active exploitation. Patch details beyond the Red Hat errata and libssh advisory URLs are not included here. Validate exact affected and fixed versions from vendor advisories before making remediation decisions.
Mitigation direction
- Apply vendor updates from RHSA-2026:18683 where applicable.
- Follow libssh and operating-system vendor guidance for fixed package versions.
- Limit SSH interactions with untrusted endpoints where operationally feasible.
- Monitor affected applications for memory growth and crashes.
Validation and detection
- Inventory libssh and libssh2 packages across affected platforms.
- Identify applications dynamically or statically linked to libssh.
- Check Red Hat CVE status for each product version.
- Confirm RHSA-2026:18683 or later relevant updates are installed.
- Review logs for crashes around SSH key exchange or rekey events.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-401: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupContainer behavior lookup
The affected technology mentions containers, so container-specific ATT&CK technique review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2025-8277 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Low
- CVSS
- 3.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L1.61.4redhatVulnerability scoring details
Base CVSS 3.1 score
3.1LowVector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:L
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- Source timelineredhat
Reported to Red Hat.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- Source timelineredhat
Made public.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- RHSA-2026:18683CVE reference, redhat · vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/security/cve/CVE-2025-8277CVE reference, redhat · vdb-entry, x_refsource_REDHAT
- RHBZ#2383888CVE reference, redhat · issue-tracking, x_refsource_REDHAT
- https://www.libssh.org/security/advisories/CVE-2025-8277.txtCVE reference, redhat
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Missing Release of Memory after Effective Lifetime
Missing Release of Memory after Effective Lifetime represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.