Security readout for executives and security teams
Plain-English summary
A remote SSH peer can repeatedly trigger failed key-exchange guesses, causing affected libssh-based software to retain memory. Continued activity may exhaust memory and crash an application, disrupting availability. The supplied assessment rates the issue low severity because exploitation requires difficult conditions and affects availability rather than data confidentiality or integrity.
Executive priority
Handle through routine vulnerability maintenance, prioritizing exposed or availability-sensitive SSH clients and affected OpenShift components. Emergency response is not supported by the supplied evidence, but unexplained memory exhaustion may justify faster remediation. Track vendor status because the affected-version information is incomplete.
Technical view
CVE-2025-8277 is a CWE-401 memory leak in libssh key-exchange handling. Memory is not released during repeated rekey operations involving incorrect KEX guesses. The reported impact is gradual memory exhaustion and possible client-side crashes, particularly with libgcrypt. CVSS 3.1 is 3.1: network-accessible, high complexity, low privileges, no user interaction, and low availability impact.
Likely exposure
Exposure primarily concerns applications using affected libssh packages and interacting with an untrusted or compromised SSH peer. The bundle lists affected RHEL 7, 8, 9, 10 and OpenShift 4 components, but version coverage is incomplete and includes a potentially confusing libssh2 entry. Confirm each installed package against Red Hat guidance.
Exploitation context
The supplied bundle does not identify public exploitation or inclusion in CISA KEV. Exploitation requires repeatedly inducing incorrect key-exchange guesses under conditions represented as high complexity and low privileges. Expected impact is memory consumption and service or client instability, not code execution or data theft.
Researcher notes
The core defect is unreleased memory across repeated KEX processing. Researchers should distinguish client-side library use from SSH server exposure and verify the cryptographic backend, especially libgcrypt. The bundle's affected-product data contains duplicate RHEL 9 entries, incomplete version bounds, and both libssh and libssh2 package names; these require vendor confirmation.
Mitigation direction
- Review RHSA-2026:18683 and deploy the vendor-prescribed package updates where applicable.
- Check libssh's advisory for supported fixed releases before upgrading non-Red Hat installations.
- Restrict SSH interactions with untrusted peers where operationally practical until remediation is complete.
- Monitor affected applications for sustained memory growth and unexpected crashes.
Validation and detection
- Inventory applications, containers, and hosts containing libssh or vendor-packaged derivatives.
- Compare installed package versions and product status with Red Hat and libssh advisories.
- Review telemetry for repeated key-exchange failures correlated with memory growth or crashes.
- After remediation, confirm package versions and verify memory remains stable during authorized resilience testing.
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.