Security readout for executives and security teams
Plain-English summary
Valkey servers running 9.0.0 through 9.0.2 can be crashed remotely before authentication if an attacker can reach the service. The bug is an availability issue, not data theft or data change, but it can interrupt applications that depend on Valkey. Valkey 9.0.3 fixes it.
Executive priority
Prioritize remediation for internet-facing or broadly reachable Valkey services because a remote unauthenticated crash can cause outages. Internal, tightly isolated deployments are lower urgency but should still be upgraded during the next controlled maintenance window.
Technical view
The issue is improper networking state reset after an empty request. A subsequent malformed RESP request can be interpreted as violating server-side invariants, triggering an assertion and aborting the server process. CVSS 7.5 reflects network reachability, low complexity, no privileges, no user interaction, and high availability impact only.
Likely exposure
Exposure is limited to valkey-io Valkey versions >=9.0.0 and <9.0.3. Risk is highest where Valkey is reachable from untrusted networks, shared tenant networks, or any client population not fully trusted. The source bundle does not identify other affected products.
Exploitation context
The vulnerability is pre-authentication and network reachable, so access control is the key boundary. The provided sources do not report active exploitation, and KEV is false. No exploit maturity details are provided beyond the vulnerability mechanics and CVSS vector.
Researcher notes
Focus validation on version range, reachability, and process-abort evidence. The root cause combines malformed RESP request handling with stale networking state after an empty request, resulting in CWE-20 and CWE-617 conditions. Avoid proof-of-concept testing against production services.
Mitigation direction
- Upgrade affected Valkey deployments to version 9.0.3 or later.
- Restrict Valkey network access to trusted clients only.
- Isolate Valkey deployments from public and untrusted networks.
- Review vendor and distribution guidance for package-specific remediation status.
Validation and detection
- Inventory Valkey instances and record exact versions.
- Confirm no production instance runs Valkey 9.0.0 through 9.0.2.
- Review network paths to ensure only trusted clients can reach Valkey.
- Check operational logs for unexpected Valkey aborts or restarts.
- Track Red Hat or vendor status if using packaged Valkey builds.
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-20: 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 lookupCWE-617: 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 lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-27623 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
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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
2 official scoresWe 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:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6GitHub_MCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6redhat-SADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- ADP timelineredhat-SADP
Made public.
- CVE publishedCVE Program
The CVE record was published.
- ADP timelineredhat-SADP
Reported to Red Hat.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2026-02-23T21:02:18.785Z: Reported to Red Hat.
- 2026-02-23T19:43:45.736Z: Made public.
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/valkey-io/valkey/security/advisories/GHSA-93p9-5vc7-8wgrCVE reference, GitHub_M · x_refsource_CONFIRM
- https://access.redhat.com/security/cve/CVE-2026-27623CVE reference, redhat-SADP · vdb-entry, x_refsource_REDHAT
- RHBZ#2442021CVE reference, redhat-SADP · issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27623.jsonCVE reference, redhat-SADP · x_sadp-csaf-vex
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.
Improper Input Validation
Improper Input Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Reachable Assertion
Reachable Assertion represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.