Security readout for executives and security teams
Plain-English summary
CommonRegexJS can be made to spend excessive CPU time when processing specially crafted input. For an exposed service, that can degrade or interrupt availability without authentication. The sources say all available versions were affected and no known patch was available at publication.
Executive priority
Treat as high priority for internet-facing or business-critical services using CommonRegexJS. The main business risk is service degradation or outage, and the source bundle states no known patch existed at publication.
Technical view
This is a Regular Expression Denial of Service issue in CommonRegexJS, tracked as CWE-1333. Vulnerable expressions can exhibit excessive backtracking on malicious input. The CVSS 4.0 score is 8.7 with network attack vector, low complexity, no privileges, no user interaction, and high vulnerable-system availability impact.
Likely exposure
Exposure is most likely in Node.js or JavaScript applications that depend on CommonRegexJS and run its parsers against untrusted or public user input, such as forms, API fields, logs, or text-processing workflows.
Exploitation context
The provided sources do not show CISA KEV listing or confirmed active exploitation. They support denial-of-service risk through crafted input, but do not establish observed exploitation in the wild.
Researcher notes
Evidence is strongest for vulnerability class, affected library, and availability impact. Evidence is incomplete on active exploitation and final remediation state. Validate actual reachability in each application before assigning incident-level urgency.
Mitigation direction
- Inventory applications and packages that include CommonRegexJS.
- Check the GitHub issue and GHSL advisory for current vendor guidance.
- Avoid using CommonRegexJS on untrusted input until a safe path is confirmed.
- Limit accepted input size before text is processed by this dependency.
- Prioritize replacement if the package remains unpatched.
Validation and detection
- Search dependency manifests and lockfiles for CommonRegexJS.
- Confirm whether reachable routes pass user-controlled text into this library.
- Review public forms, APIs, and background text-processing jobs for exposure.
- Track whether any maintained patch, fork, or replacement is adopted.
- Verify availability monitoring covers CPU saturation and request latency.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-1333: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-26305 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.7 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Green
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Green——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
8.7HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/U:Green
Source materials
- CVE List V5 sourceCVE List V5
- https://securitylab.github.com/advisories/GHSL-2020-291-redos-CommonRegexJS/CVE reference
- https://github.com/talyssonoc/CommonRegexJS/issues/4CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Inefficient Regular Expression Complexity
Inefficient Regular Expression Complexity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.