Regular expression denial of service in deno
Priority HIGH 72CWE-1333Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-1333.
Summary
Versions of the package deno before 1.31.0 are vulnerable to Regular Expression Denial of Service (ReDoS) due to the upgradeWebSocket function, which contains regexes in the form of /s*,s*/, used for splitting the Connection/Upgrade header. A specially crafted Connection/Upgrade header can be used to significantly slow down a web socket server.
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.01229 69th percentileScored 2026-11-07
Fix Fixed deno: 1.31.0deno (crates.io): 1.31.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | deno | before 1.31.0 | 1.31.0 | Patch available | CNA |
| — | deno (crates.io) | 1.12.0 to before 1.31.0 | 1.31.0 | Patch available | GHSA-jc97-h3h9-7xh6 |
- deno Vendor— Affected before 1.31.0 Fixed in 1.31.0 Patch available CNA
- deno (crates.io) Vendor— Affected 1.12.0 to before 1.31.0 Fixed in 1.31.0 Patch available GHSA-jc97-h3h9-7xh6
Remediation
- Fix · CNA deno Fixed in 1.31.0
- Fix · GHSA-jc97-h3h9-7xh6 deno (crates.io) Fixed in 1.31.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2023-26103
- 2026-10-03 Alias added: GHSA-jc97-h3h9-7xh6
References
Patch 2
Other 5
- https://github.com/denoland/deno/blob/2b247be517d789a37e532849e2e40b724af0918f/ext/http/01_http.js%23L395-L409
- https://github.com/denoland/deno/releases/tag/v1.31.0
- https://github.com/denoland/deno/security/advisories/GHSA-jc97-h3h9-7xh6
- https://github.com/denoland/deno
- https://github.com/denoland/deno/blob/2b247be517d789a37e532849e2e40b724af0918f/ext/http/01_http.js#L395-L409
More denoland Deno vulnerabilities
- TI-2026-21627 Deno has a Command Injection via Incomplete shell metacharacter blocklist in node:child_process CVSS 3.1CRITICAL 9.8
- TI-2025-17782 Deno's AES GCM authentication tags are not verified CVSS 4.0HIGH 7.7
- TI-2024-18537 *const c_void / ExternalPointer unsoundness leading to use-after-free CVSS 3.1HIGH 8.8
- TI-2024-18536 Deno arbitrary file descriptor close via `op_node_ipc_pipe()` leading to permission prompt bypass CVSS 3.1HIGH 8.8
- TI-2023-12990 Deno is vulnerable to interactive `run` permission prompt spoofing via improper ANSI neutralization CVSS 3.1HIGH 8.8
- TI-2024-18539 Deno interactive permission prompt spoofing via improper ANSI stripping CVSS 3.1HIGH 8.8
Sources
- CVE-2023-26103 · CVE Program
- CVE-2023-26103 · NVD
- FIRST EPSS
- GHSA-jc97-h3h9-7xh6 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences