How severe is CVE-2021-27293?

CVE-2021-27293 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-27293 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-27293?

CVE-2021-27293 primarily affects Restsharp. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-27293?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-27293 published?

CVE-2021-27293 was published on 2021-07-12 and last updated on 2026-06-17.

CVE-2021-27293

Q: What is CVE-2021-27293?

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.

CVE-2021-27293 is a high-severity vulnerability in Restsharp with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-697.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (71st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-697
Affected product: Restsharp
Published: 2021-07-12
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-27293?: 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.
How severe is CVE-2021-27293?: CVE-2021-27293 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-27293 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-27293?: CVE-2021-27293 primarily affects Restsharp. In total, 9 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-27293?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-27293 published?: CVE-2021-27293 was published on 2021-07-12 and last updated on 2026-06-17.

References

Affected products (9)

cpe:2.3:a:restsharp:restsharp:*:*:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.10:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.11:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.12:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.2:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.3:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.4:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.6:*:*:*:*:*:*
cpe:2.3:a:restsharp:restsharp:106.11.8:alpha0.7:*:*:*:*:*:*

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