RCE in Spip

CVE-2026-77806

SPIP before 4.4.21 allows unauthenticated remote attackers to execute arbitrary code, as exploited in the wild in August 2026. This is related to code injection via an X-Spip-Filtre HTTP request header that is mishandled by analyse_resultat_skel.

Vulnerability class: RCE (Remote Code Execution)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.045 (91.2th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 91st percentile — 91.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-77806: held from 0.042 to 0.045.

EPSS over last 30 days · oldest: 0.042 · newest: 0.045 · change: +0.003

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-77806?
CVE-2026-77806 is a critical-severity vulnerability in Spip, classified under Code Injection. CVSS score: 9.8/10. Published 2026-08-21.
How severe is CVE-2026-77806?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2026-77806 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.