CVE-2026-8888: Version 3.0.7 of the Securly Chrome Extension downloads config.json over HTTP and compiles server-provided pat

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HIGH 7.5REMOTEDOWNGRADE

CVE-2026-8888 is a high-severity flaw (CVSS 7.5) affecting securly. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Weakness	CWE-917, CWE-1333
Published	2026-06-03
Last modified	2026-07-22

Publisher (CNA): CERT/CC · Vendor: securly

Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-03 19:16 UTCPublished CVE record published
2026-07-22 20:10 UTCUpdated Record last modified

securly securly DOWNGRADE

Affected: 3.0.7

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.0.7

1. Check installed version

apt-cache policy securly || rpm -q securly || securly --version

2. No fixed release: DOWNGRADE to a release before 3.0.7 (Debian / Ubuntu)

apt-cache madison securly sudo apt install securly=<VERSION_BEFORE_3.0.7> sudo apt-mark hold securly

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list securly sudo dnf downgrade securly-<VERSION_BEFORE_3.0.7> sudo dnf versionlock add securly

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8888?

securly: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-8888 being exploited?

CVE-2026-8888 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8888 affect?

CVE-2026-8888 affects securly. Severity is high (CVSS 7.5). 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 pa

How urgent is CVE-2026-8888?

Priority 41/100. High severity; Remotely exploitable, no login, no user action

Software pages

Google Chrome vulnerabilities

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References

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