CVE-2021-27293
Incorrect Regular Expression in RestSharp
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
CVE-2021-27293- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-697
- Updated
- 2026-11-02
CVE List No score
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
CVE-2021-27293- Updated
- 2026-11-02
EUVDEUVD-2021-1455 No score
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
EUVD-2021-1455- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-9pq7-rcxv-47vq
Incorrect Regular Expression in RestSharp
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
GHSA-9pq7-rcxv-47vq- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-185, CWE-697
- Updated
- 2026-11-02
OSV
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
CVE-2021-27293- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVGHSA-9pq7-rcxv-47vq
Incorrect Regular Expression in RestSharp
RestSharp < 106.11.8-alpha.0.13 uses a regular expression which is vulnerable to Regular Expression Denial of Service (ReDoS) when converting strings into DateTimes. If a server responds with a malicious string, the client using RestSharp will be stuck processing it for an exceedingly long time. Thus the remote server can trigger Denial of Service.
- Record
GHSA-9pq7-rcxv-47vq- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-185, CWE-697
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
RestSharpNuGet |
through 106.11.7 | 106.11.8-alpha.0.13 |
RestSharpNuGet |
before 106.11.8-alpha.0.13, plus listed versions 1.0.0100.3.0101.0.0101.1.0101.2.0 Show 45 moreShow less101.3.0102.0.0102.1.0102.2.0102.3.0102.4.0102.5.0102.6.0102.7.0103.0.0103.0.0-nojsondotnet103.1.0103.1.0-beta103.2.0103.3.0103.4.0104.0.0104.1.0104.2.0104.2.0-beta104.3.0-beta104.3.1-beta104.3.3104.3.3-beta104.4.0104.4.0-beta104.4.0-rc1104.5.0104.5.0-beta105.0.0105.0.1105.1.0105.2.0105.2.1105.2.2105.2.3106.0.0106.0.0-alpha0277106.0.0-alpha0281106.0.0-alpha0282106.0.0-alpha0283106.0.0-alpha0284106.0.1106.1.0106.1.0-alpha0038 |
106.11.8-alpha.0.13 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27293 is a high vulnerability (CVSS 7.5) in Restsharp, published July 12, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.51%, the 74th percentile. Fixed in RestSharp 106.11.8-alpha.0.13.
References
Left out here: 43 versions. The JSON record has them.