Is CVE-2021-34549 in the CISA KEV catalog?

No. CVE-2021-34549 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-34549?

CVE-2021-34549 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2021-34549?

CVE-2021-34549 has an EPSS score of 1.61% (73th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-34549?

Upgrade tor on debian 11 to 0.4.5.9-1 or later. Fixes are available for 2 affected products.

CVE & CISA-KEV Catalog

CVE-2021-34549

HIGHEPSS 73th pctl

7.5

CVSS v3

NVD

Description

An issue was discovered in Tor before 0.4.6.5, aka TROVE-2021-005. Hashing is mishandled for certain retrieval of circuit data. Consequently. an attacker can trigger the use of an attacker-chosen circuit ID to cause algorithm inefficiency.

CWE-400Resource Exhaustion

How to fix

Remediation Available

torDebian

Fixed in:0.4.5.9-1CVE-2021-34549

torUbuntu

Fixed in:0.2.4.27-1ubuntu0.1+esm2USN-5036-1

Fixed in:0.2.9.14-1ubuntu1~16.04.3+esm1USN-5036-1

Fixed in:0.3.2.10-1ubuntu0.2~esm2USN-5036-1

Fixed in:0.4.2.7-1ubuntu0.1~esm1USN-5036-1

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

1.61%probability of exploitation in 30 days

73rdpercentile

Elevated risk: more likely to be exploited than 73% of all known CVEs.

References

Vendor Advisory1

blog.torproject.org

Third-Party Advisory1

security.gentoo.org

Other references1

gitlab.torproject.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.