CVE-2023-28755

A ReDoS issue was discovered in the URI component through 0.12.0 in Ruby through 3.2.1. The URI parser mishandles invalid URLs that have specific characters. It causes an increase in execution time for parsing strings to URI objects. The fixed versions are 0.12.1, 0.11.1, 0.10.2 and 0.10.0.1.

Published: 2023-03-31 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-28755 is rated Moderate Risk (52.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.64%). Core evidence: EPSS rose +2.33% over the last day, indicating growing attacker interest. Mandatory action: Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-28755

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.31% 2.64% +2.33%
2 2026-06-10 0.37% 0.31% -0.05%
3 2026-06-08 0.37%

Full EPSS history (51 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-28755

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
3.9 1.4 [email protected]
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-28755

GitHub Security Advisory for CVE-2023-28755

GHSA-hv5j-3h9f-99c2 · Severity: high · Ecosystem: rubygems — Ruby URI component ReDoS issue

OS Trackers for CVE-2023-28755

vendor priority summary link
alpine CVE-2023-28755: 1 source package rows (ruby); 7 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 0. https://security.alpinelinux.org/vuln/CVE-2023-28755
debian not yet assigned CVE-2023-28755 not yet assigned priority: Debian including 4 source packages (jruby, ruby2.7, ruby3.1, rubygems), 11 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 9, open 2. https://security-tracker.debian.org/tracker/CVE-2023-28755
gentoo normal CVE-2023-28755: 1 GLSA(s) (202401-27), 1 atom(s) (dev-lang/ruby); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-28755
redhat medium https://access.redhat.com/security/cve/CVE-2023-28755
suse medium CVE-2023-28755 severity moderate: SUSE including 364 source package names (2.17-17.3:libruby2_5-2_5-2.5.9-150000.4.29.1, 2.17-17.3:ruby2.5-2.5.9-150000.4.29.1, …), 990 product×package rows across 196 product lines (Container bci/ruby, Container suse/rmt-server, … (196 product lines)): Fixed 681, Known Affected 231, Known Not Affected 78. https://www.suse.com/security/cve/CVE-2023-28755/
ubuntu medium CVE-2023-28755 medium priority: Ubuntu including 9 source packages (jruby, ruby1.9.1, …), 117 status rows across 13 suites (bionic, focal, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 72, ignored 17, needs-triage 10, released 10, not-affected 5, needed 3. https://ubuntu.com/security/CVE-2023-28755

Affected software / configurations for CVE-2023-28755

Vendor Product Version Raw CPE
ruby-lang uri <= 0.10.0 cpe:2.3:a:ruby-lang:uri:*:*:*:*:*:ruby:*:*
ruby-lang uri 0.10.1 cpe:2.3:a:ruby-lang:uri:0.10.1:*:*:*:*:ruby:*:*
ruby-lang uri 0.11.0 cpe:2.3:a:ruby-lang:uri:0.11.0:*:*:*:*:ruby:*:*
ruby-lang uri 0.12.0 cpe:2.3:a:ruby-lang:uri:0.12.0:*:*:*:*:ruby:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
fedoraproject fedora 36 cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
fedoraproject fedora 37 cpe:2.3:o:fedoraproject:fedora:37:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

References for CVE-2023-28755

URL Tags
https://github.com/ruby/uri/releases/ Release Notes
https://lists.debian.org/debian-lts-announce/2023/04/msg00033.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/27LUWREIFTP3MQAW7QE4PJM4DPAQJWXF/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FFZANOQA4RYX7XCB42OO3P24DQKWHEKA/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G76GZG3RAGYF4P75YY7J7TGYAU7Z5E2T/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QA6XUKUY7B5OLNQBLHOT43UW7C5NIOQQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WMIOPLBAAM3FEQNAXA2L7BDKOGSVUT5Z/
https://security.gentoo.org/glsa/202401-27
https://security.netapp.com/advisory/ntap-20230526-0003/ Third Party Advisory
https://www.ruby-lang.org/en/downloads/releases/ Release Notes
https://www.ruby-lang.org/en/news/2022/12/25/ruby-3-2-0-released/ Release Notes
https://www.ruby-lang.org/en/news/2023/03/28/redos-in-uri-cve-2023-28755/ Vendor Advisory
https://lists.debian.org/debian-lts-announce/2024/09/msg00000.html
https://lists.debian.org/debian-lts-announce/2025/05/msg00015.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/27LUWREIFTP3MQAW7QE4PJM4DPAQJWXF/
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