Security readout for executives and security teams
Plain-English summary
This critical SPIP flaw can let an unauthenticated internet attacker take control of a vulnerable website. Successful exploitation could expose data, alter content, install malicious code, or disrupt service. The supplied CVE record states that versions before 4.4.21 are vulnerable and that exploitation occurred in August 2026.
Executive priority
Treat this as an emergency remediation item for internet-facing SPIP. Assign ownership immediately, upgrade within hours where feasible, and investigate previously exposed vulnerable systems. Business leaders should expect possible service interruption during containment and should ensure incident-response coverage is available.
Technical view
CVE-2026-77806 is a CWE-94 code-injection vulnerability in SPIP's analyse_resultat_skel handling of the X-Spip-Filtre HTTP header. It permits unauthenticated remote code execution with low complexity and no user interaction. CVSS 3.1 is 9.8, reflecting high confidentiality, integrity, and availability impact.
Likely exposure
Internet-accessible SPIP deployments running a release before 4.4.21 are the primary concern. Internal instances may also be reachable by compromised users or systems. The bundle's affected-version metadata is inconsistent, so organizations should verify versions against the vendor bulletin rather than rely solely on automated CPE matching.
Exploitation context
The supplied CVE description reports exploitation in the wild during August 2026. The vulnerability is not marked as CISA KEV in the bundle. References also include a public Metasploit pull request, indicating public exploit-development activity, although its merge and operational status are not established here.
Researcher notes
The central risk is pre-authentication remote code execution through mishandled request-header data. Version scope is stated as SPIP before 4.4.21, but the structured affected entry lists version "0" with default status unaffected, creating uncertainty for automated scanners. Confirm scope using installed versions and the vendor advisory. No exploit mechanics should be required for defensive validation.
Mitigation direction
- Upgrade every SPIP deployment below 4.4.21 to version 4.4.21 or a later vendor-supported release.
- Follow the SPIP critical security update bulletin for deployment instructions and any vendor-approved compensating controls.
- Restrict internet access to vulnerable instances until upgrading and validation are complete.
- Initiate incident response if logs or systems show suspicious activity consistent with this vulnerability.
Validation and detection
- Inventory all SPIP deployments, including externally hosted, development, staging, and forgotten instances.
- Confirm each deployed SPIP version is 4.4.21 or later and supported by the vendor.
- Review HTTP logs for unexpected X-Spip-Filtre header activity and correlate findings with application and system events.
- Check vulnerable or previously exposed hosts for unauthorized files, processes, accounts, configuration changes, and outbound connections.
- After upgrading, verify normal site operation and confirm the vulnerable release is no longer served.
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-94: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-77806 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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
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:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9mitreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
- 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
- https://github.com/rapid7/metasploit-framework/pull/21790CVE reference, mitre
- https://blog.spip.net/Mise-a-jour-critique-de-securite-sortie-de-SPIP-4-4-21.htmlCVE reference, mitre
- https://github.com/rapid7/metasploit-framework/pull/21790/commits/b16eca819abb8f1401f21d115e71e3dfc67b847cCVE reference, mitre
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 Control of Generation of Code
Improper Control of Generation of Code represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.