CVE-2026-35611: Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-35611 is a high-severity flaw (CVSS 7.5) affecting addressable. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerable to catastrophic backtracking. Templates using the * (explode) modifier with any expansion operator (e.g., {foo*}, {+var*}, {#var*}, {/var*}, {.var*}, {;var*}, {?var*}, {&var*}) generate p

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

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 71%)
CISA exploited list	No
Weakness	CWE-1333
Published	2026-04-07
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: addressable project

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-07 17:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

addressable project addressable UPGRADE

Affected: >= 2.3.0 and < 2.9.0

Fixed in: 2.9.0

Safe to downgrade to: a release before 2.3.0

1. Check installed version

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

2. UPGRADE to 2.9.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade addressable

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade addressable

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.3.0 (Debian / Ubuntu)

apt-cache madison addressable sudo apt install addressable=<VERSION_BEFORE_2.3.0> sudo apt-mark hold addressable

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list addressable sudo dnf downgrade addressable-<VERSION_BEFORE_2.3.0> sudo dnf versionlock add addressable

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-2026-35611?

addressable: upgrade to 2.9.0. Exact commands for each OS are on this page.

Is CVE-2026-35611 being exploited?

CVE-2026-35611 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-2026-35611 affect?

CVE-2026-35611 affects addressable. Severity is high (CVSS 7.5). Addressable is an alternative implementation to the URI implementation that is part of Ruby's standard library. From 2.3.0 to before 2.9.0, within the URI template implementation in Addressable, two classes of URI template generate regular

How urgent is CVE-2026-35611?

Priority 39/100. High severity; Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

References

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