CVE-2026-35611

highpriority · track · 0EPSS 0.004 · 30 %ileDEEURUUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.36% (30th) EPSS
CVSS 7.5 · high
Is it mine?
10 products
Check your exposure
Who says so?
6 sources
cnnvd · enisa_euvd · fstec_bdu · cert_bund

EPSS · scored 2026-10-27

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 patterns with nested unbounded quantifiers that are O(2^n) when matched against a maliciously crafted URI. Templates using multiple variables with the + or # operators (e.g., {+v1,v2,v3}) generate patterns with O(n^k) complexity due to the comma separator being within the matched character class, causing ambiguous backtracking across k variables. When matched against a maliciously crafted URI, this can result in catastrophic backtracking and uncontrolled resource consumption, leading to denial of service. This vulnerability is fixed in 2.9.0.

01

cvss

Technical severity, 0–10. One row per scoring source.

7.5
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · FSTEC (BDU) RU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comexploitability 3.9 · impact 3.6
v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV
v3.16.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

affected products (10)

Products and version ranges known to be affected.

05

advisories (2)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-1687IBM License Metric Tool: Mehrere Schwachstellen ermöglichen nicht spezifizierten AngriffDeutsch2026-05-26csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in IBM License Metric Tool ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.

  • GHSA-h27x-rffw-24p4Addressable has a Regular Expression Denial of Service in Addressable templates2026-04-08ghsa · osvUS

    ### Impact Within the URI template implementation in Addressable, two classes of URI template generate regular expressions vulnerable to catastrophic backtracking: 1. Templates using the `*` (explode) modifier with any expansion operator (e.g., `{foo*}`, `{+var*}`, `{#var*}`, `{/var*}`, `{.var*}`, `{;var*}`, `{?var*}`, `{&var*}`) generate patterns with nested unbounded quantifiers that are O(2^n) when matched against a maliciously crafted URI. 2. Templates using multiple variables with the `+` or `#` operators (e.g., `{+v1,v2,v3}`) generate patterns with O(n^k) complexity due to the comma separator being within the matched character class, causing ambiguous backtracking across k variables. When matched against a maliciously crafted URI, this can result in catastrophic backtracking and uncontrolled resource consumption, leading to denial of service. The first pattern was partially addressed in 2.8.10 for certain operator combinations. Both patterns are fully remediated in 2.9.0. Users of the URI parsing capabilities in Addressable but not the URI template matching capabilities are unaffected. ### Affected Versions This vulnerability affects Addressable >= 2.3.0 (note: 2.3.0 and 2.3.1 were yanked; the earliest installable release is 2.3.2). It was partially fixed in version 2.8.10 and fully remediated in 2.9.0. The vulnerability is more exploitable on MRI Ruby < 3.2 and on all versions of JRuby and TruffleRuby. MRI Ruby 3.2 and later ship with Onigmo 6.9, which introduces memoization that prevents catastrophic backtracking for the first class of template. JRuby and TruffleRuby do not implement equivalent memoization and remain vulnerable to all patterns. This has been confirmed on the following runtimes: | Runtime | Status | |---------|--------| | MRI Ruby 2.6 | Vulnerable | | MRI Ruby 2.7 | Vulnerable | | MRI Ruby 3.0 | Vulnerable | | MRI Ruby 3.1 | Vulnerable | | MRI Ruby 3.2 | Partially vulnerable | | MRI Ruby 3.3 | Partially vulnerable | | MRI Ruby 3.4 | Partially vulnerable | | MRI Ruby 4.0 | Partially vulnerable | | JRuby 10.0 | Vulnerable | | TruffleRuby 21.2 | Vulnerable | ### Workarounds - **Upgrade to MRI Ruby 3.2 or later**, if your application does not use JRuby or TruffleRuby. The Onigmo memoization introduced in MRI Ruby 3.2 prevents catastrophic backtracking from nested unbounded quantifiers (pattern 1 above — templates using the `*` modifier). It does not reliably mitigate the O(n^k) multi-variable case (pattern 2), so upgrading Ruby alone may not be sufficient if your templates use `{+v1,v2,...}` or `{#v1,v2,...}` syntax. - **Avoid using vulnerable template patterns** when matching user-supplied input on unpatched versions of the library: - Templates using the `*` (explode) modifier: `{foo*}`, `{+var*}`, `{#var*}`, `{.var*}`, `{/var*}`, `{;var*}`, `{?var*}`, `{&var*}` - Templates using multiple variables with the `+` or `#` operators: `{+v1,v2}`, `{#v1,v2,v3}`, etc. - **Apply a short timeout** around any call to `Template#match` or `Template#extract` that processes user-supplied data. ### References - https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS - https://cwe.mitre.org/data/definitions/1333.html - https://www.regular-expressions.info/catastrophic.html ### Credits Discovered in collaboration with @jamfish. ### For more information If you have any questions or comments about this advisory: * [Open an issue](https://github.com/sporkmonger/addressable/issues)

06

also known as (3)

Other names and identifiers for this entity.

07

sources

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08

references (4)

External citations — patches, advisories, analysis.

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