RCE in Securly
CVE-2026-8888
Version 3.0.7 of the Securly Chrome Extension downloads config.json over HTTP and compiles server-provided patterns as JavaScript regular expressions via new RegExp() without complexity validation. An on-path attacker can inject specific patterns to cause catastrophic backtracking, resulting in denial of service on all browsing.
Vulnerability class: Log4Shell (CVE-2021-44228)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 46.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Securly — versions 3.0.7
- Securly Chrome Extension — versions 0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- kb.cert.org/vuls/id/595768 (VDB Entry, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-8888?
- CVE-2026-8888 is a high-severity vulnerability in Securly, classified under Improper Neutralization of Special Elements used in an Expression Language Statement (Expression Language Injection). CVSS score: 7.5/10. Published 2026-06-03.
- How severe is CVE-2026-8888?
- High severity. CVSS v3 base score is 7.5 out of 10.
- Is CVE-2026-8888 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.