Security readout for executives and security teams
Plain-English summary
CVE-2021-29059 is a denial-of-service risk in the JavaScript is-svg package. If an application checks attacker-controlled invalid SVG text with affected versions, regex processing can consume excessive CPU and slow or interrupt service.
Executive priority
Prioritize remediation where public users can submit SVG or image content. Internal-only or non-SVG paths are lower urgency, but dependency cleanup is still appropriate.
Technical view
The CVE describes a Regular Expression Denial of Service in is-svg versions 2.1.0 through 4.2.2 and below. The trigger condition is validation of a crafted invalid SVG string. No CVSS score or CWE is provided in the source bundle.
Likely exposure
Exposure is most likely in Node.js applications that depend on is-svg and validate untrusted SVG content, such as uploads, image processing, or content ingestion paths.
Exploitation context
The source bundle includes a public PoC reference, but KEV is false and no cited source states active exploitation. Treat exploit status as unconfirmed beyond public disclosure.
Researcher notes
The record lacks CVSS, CWE, and detailed affected CPE data. The strongest facts are package name, affected version range, ReDoS class, crafted invalid SVG trigger, and public PoC reference.
Mitigation direction
- Identify applications using is-svg versions 2.1.0 through 4.2.2 or below.
- Move off the affected version range; review the referenced v4.3.0 release.
- Restrict or reject untrusted SVG validation where possible.
- Apply request size and processing time controls around SVG ingestion.
- Check vendor guidance before relying on any compensating control.
Validation and detection
- Review package manifests and lockfiles for is-svg dependency versions.
- Trace whether untrusted SVG strings reach is-svg validation.
- Prioritize internet-facing upload or image ingestion features.
- Confirm deployed builds use a version outside the affected range.
- Monitor service latency and CPU anomalies on SVG-handling routes.
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.
CVE-2021-29059 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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 and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.npmjs.com/package/is-svgCVE reference · x_refsource_MISC
- https://github.com/yetingli/SaveResults/blob/main/js/is-svg.jsCVE reference · x_refsource_MISC
- https://github.com/sindresorhus/is-svg/releases/tag/v4.3.0CVE reference · x_refsource_MISC
- https://github.com/yetingli/PoCs/blob/main/CVE-2021-29059/IS-SVG.mdCVE reference · x_refsource_MISC
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.