GHSA-w8qv-6jwh-64r5 CVE-2021-23364
Regular Expression Denial of Service in browserslist
Medium
npm
- Severity
- 5.3 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 2.38%
- Chance of exploitation in the next 30 days. Higher than 83.91% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
4.16.5- Upgrade browserslist to this version or later
Description
The package browserslist from 4.0.0 and before 4.16.5 are vulnerable to Regular Expression Denial of Service (ReDoS) during parsing of queries.
Affected versions
npm
| Package | Vulnerable | Fixed in |
|---|---|---|
| browserslist | >= 4.0.0, < 4.16.5 |
4.16.5 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
browserslist npm → 4.16.5
- npm
npm install browserslist@4.16.5- yarn
yarn add browserslist@4.16.5- pnpm
pnpm add browserslist@4.16.5
Severity breakdown
CVSS 3.1 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Weakness
CWE-1333: Inefficient Regular Expression Complexity
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
How to prevent it
- Architecture and Design: Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
- System Configuration: Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
- Implementation: Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
- Implementation: Limit the length of the input that the regular expression will process.
CWE-400: Uncontrolled Resource Consumption
The product does not properly control the allocation and maintenance of a limited resource.
How to prevent it
- Architecture and Design: Design throttling mechanisms into the system architecture. The best protection is to limit the amount of resources that an unauthorized user can cause to be expended. A strong authentication and access control model will help prevent such attacks from occurring in the first place. The login application should be protected against DoS attacks as much as possible. Limiting the database access, perhaps by caching result sets, can help minimize the resources expended. To further limit the potential for a DoS attack, consider tracking the rate of requests received from users and blocking requests that exceed a defined rate threshold.
- Architecture and Design: Mitigation of resource exhaustion attacks requires that the target system either: recognizes the attack and denies that user further access for a given amount of time, or uniformly throttles all requests in order to make it more difficult to consume resources more quickly than they can again be freed. The first of these solutions is an issue in itself though, since it may allow attackers to prevent the use of the system by a particular valid user. If the attacker impersonates the valid user, they may be able to prevent the user from accessing the server in question. The second solution is simply difficult to effectively institute -- and even when properly done, it does not provide a full solution. It simply makes the attack require more resources on the part of the attacker.
- Architecture and Design: Ensure that protocols have specific limits of scale placed on them.
- Implementation: Ensure that all failures in resource allocation place the system into a safe posture.
References
Advisories
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-c83g-rgw3-j3cx Browserslist: Unbounded memory growth (no cache eviction) via distinct query results, leading to eventual OOM | High | Also affects browserslist |
| GHSA-73wf-gq98-2v4g Browserslist: Uncaught crash / prototype write via untrusted browserslist-stats.json custom stats (normalizeStats) | High | Also affects browserslist |
| GHSA-7wch-p9px-956x Forge: Regular expression denial of service in PEM decoding (pem.decode) | High | Same weakness, CWE-1333 |
| GHSA-xcq7-p3pf-p88h OpenTelemetry Python: Unbounded tracestate parsing in opentelemetry-api | Medium | Same weakness, CWE-1333 |
| GHSA-xgh8-jp6q-p5x8 Pillow: ReDoS in XbmImagePlugin: 512-byte file stalls Image.open() for minutes | High | Same weakness, CWE-1333 |
| GHSA-rxp7-6hxx-x8q5 ip-address: Address6 matches a zone identifier in quadratic time ahead of its length limit, allowing a single long string to stall the process | Medium | Same weakness, CWE-1333 |
| GHSA-r925-mgvr-h9cc Symfony: ReDoS in HeaderUtils::split() Reachable Through the Cache-Control Request Header | High | Same weakness, CWE-1333 |
| GHSA-4ffr-jq9g-5ffx Nodemailer: Quadratic backtracking in SMTP AUTH mechanism detection regexes allows pre-auth remote denial of service | High | Same weakness, CWE-1333 |
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