Is CVE-2021-21240 in the CISA KEV catalog?

No. CVE-2021-21240 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21240?

CVE-2021-21240 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-21240?

CVE-2021-21240 has an EPSS score of 3.88% (89th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21240?

Upgrade python-httplib2 on debian 12 to 0.20.2-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-21240

HIGHEPSS 89th pctl

7.5

CVSS v3

NVD

Description

httplib2 is a comprehensive HTTP client library for Python. In httplib2 before version 0.19.0, a malicious server which responds with long series of "\xa0" characters in the "www-authenticate" header may cause Denial of Service (CPU burn while parsing header) of the httplib2 client accessing said server. This is fixed in version 0.19.0 which contains a new implementation of auth headers parsing using the pyparsing library.

CWE-400Resource Exhaustion

How to fix

Remediation Available

python-httplib2Debian

Fixed in:0.20.2-1CVE-2021-21240

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

3.88%probability of exploitation in 30 days

89thpercentile

Elevated risk: more likely to be exploited than 89% of all known CVEs.

References

Patch2

Exploit1

github.com

Third-Party Advisory1

pypi.org

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-44487	High	7.5	100%	KEV	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2011-3192	High	7.8	99%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2024-25617	Medium	5.3	89%	-	Fix
CVE-2018-1000115	High	7.5	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.