PatchTheCVECVE-2020-7663: websocket-extensions ruby module prior to 0.1.5 allows Denial of Service (DoS) via Regex Backtracking
CVE-2020-7663 is a high-severity flaw (CVSS 7.5) affecting websocket-extensions, debian linux, ubuntu linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
websocket-extensions ruby module prior to 0.1.5 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repeating two-byte sequence of a backslash and some other character. This could be abused by an attacker to conduct Regex Denial Of Service (ReDoS) on a single-threaded server by providing a malicious payload with t
Why this priority
- High severity
- EPSS top 8%: very likely to be exploited
- Public exploit reference
- Remotely exploitable, no login, no user action
- On your watchlist
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 4.6% (top 8%) |
| CISA exploited list | No |
| Published | 2020-06-02 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2020-7663?
websocket-extensions: upgrade to 0.1.5; debian linux: mitigate or apply the listed mitigation; ubuntu linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2020-7663 being exploited?
CVE-2020-7663 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2020-7663 affect?
CVE-2020-7663 affects websocket-extensions, debian linux, ubuntu linux. Severity is high (CVSS 7.5). websocket-extensions ruby module prior to 0.1.5 allows Denial of Service (DoS) via Regex Backtracking. The extension parser may take quadratic time when parsing a header containing an unclosed string parameter value whose content is a repea
How urgent is CVE-2020-7663?
Priority 64/100. High severity; EPSS top 8%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist
Software pages
Ubuntu vulnerabilities · Debian vulnerabilities · Ruby vulnerabilities
Related CVEs
- CVE-2020-7662 HIGH 7.5 UPGRADE websocket-extensions npm module prior to 0.1.4 allows Denial of Service (DoS) via Regex Backtracking