How severe is CVE-2025-10990?

CVE-2025-10990 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-10990?

CVE-2025-10990 affects the following packages: rexml (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2025-10990?

Update rexml to 3.3.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-10990 is resolved across your whole dependency graph.

How do I detect CVE-2025-10990 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rexml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-10990 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2025-10990 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-10990 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-10990?

CVE-2025-10990 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 46th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-10990?

CVE-2025-10990 is classified as CWE-1333 (CWE-1333). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2025-10990 published, and has it been updated?

CVE-2025-10990 was published on February 27, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎

💎 RubyGems

Not in CISA KEV

HIGH severity

CVE-2025-10990 — rexml

HIGHFix: ruby/rexml@ce59f2e

CVE-2025-10990 is a high-severity (CVSS 7.5) CWE-1333 vulnerability in rexml. A fix is available for rexml — see the affected versions and patch details below.

Rexml: rexml: denial of service via inefficient regex parsing

Also known asCVE-2024-49761 GHSA-2rxp-v6pw-ch6m

Published

Feb 27, 2026

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-10990.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs46th percentile — riskier than 46% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

💎rexml

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The REXML gem before 3.3.9 has a ReDoS vulnerability when it parses an XML that has many digits between &# and x...; in a hex numeric character reference (&#x...;).

This does not happen with Ruby 3.2 or later. Ruby 3.1 is the only affected maintained Ruby. Note that Ruby 3.1 will reach EOL on 2025-03.

Patches

The REXML gem 3.3.9 or later include the patch to fix the vulnerability.

Workarounds

Use Ruby 3.2 or later instead of Ruby 3.1.

References

https://www.ruby-lang.org/en/news/2024/10/28/redos-rexml-cve-2024-49761/: An announce on www.ruby-lang.org

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`rexml`	all versions	3.3.9`bundle update rexml --conservative`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for rexml, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update rexml to 3.3.9 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-10990 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

This vulnerability is rated as a moderate severity because it allows attackers to exploit inefficient regex parsing in hex numeric character references (&#x...;), causing a ReDoS and impacting availability, it requires specific malicious input but does not affect confidentiality or integrity. Satellite employs…

Workaround published by Red Hat

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.

Source: Red Hat security advisory for CVE-2025-10990 (CC BY 4.0)

Product	Fixed in	Advisory
Red Hat Satellite 6.16 for RHEL 8	`puppet-agent-0:8.8.1-3.el8sat`	RHSA-2025:17613
Red Hat Satellite 6.17 for RHEL 9	`puppet-agent-0:8.8.1-3.el9sat`	RHSA-2025:17606
Satellite Client 6 for RHEL 8	`puppet-agent-0:7.34.0-4.el8sat`	RHSA-2025:17693

Frequently Asked Questions

### Impact The REXML gem before 3.3.9 has a ReDoS vulnerability when it parses an XML that has many digits between `&#` and `x...;` in a hex numeric character reference (`&#x...;`). This does not happen with Ruby 3.2 or later. Ruby 3.1 is the only affected maintained Ruby. Note that Ruby 3.1 will reach EOL on 2025-03. ### Patches The REXML gem 3.3.9 or later include the patch to fix the vulnerability. ### Workarounds Use Ruby 3.2 or later instead of Ruby 3.1. ### References * https://www.ruby-lang.org/en/news/2024/10/28/redos-rexml-cve-2024-49761/: An announce on www.ruby-lang.org

O3 Security · Impact-Aware SCA

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