How severe is CVE-2021-38161?

CVE-2021-38161 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-38161 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-38161?

CVE-2021-38161 primarily affects Apache Traffic Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-38161?

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-2021-38161 published?

CVE-2021-38161 was published on 2021-11-03 and last updated on 2026-06-17.

CVE-2021-38161

CVE-2021-38161 is a high-severity vulnerability in Apache Traffic Server with a CVSS 3.x base score of 8.1. 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-287.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v2: 6.8
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Apache Traffic Server
Published: 2021-11-03
Last modified: 2026-06-17

Description

Improper Authentication vulnerability in TLS origin verification of Apache Traffic Server allows for man in the middle attacks. This issue affects Apache Traffic Server 8.0.0 to 8.0.8.

Frequently asked questions

What is CVE-2021-38161?: Improper Authentication vulnerability in TLS origin verification of Apache Traffic Server allows for man in the middle attacks. This issue affects Apache Traffic Server 8.0.0 to 8.0.8.
How severe is CVE-2021-38161?: CVE-2021-38161 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-38161 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-38161?: CVE-2021-38161 primarily affects Apache Traffic Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-38161?: 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-2021-38161 published?: CVE-2021-38161 was published on 2021-11-03 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:apache:traffic_server:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

More vulnerabilities in Apache Traffic Server

CVE-2014-3525 — Critical (CVSS 10.0): Unspecified vulnerability in Apache Traffic Server 3.x through 3.2.5, 4.x before 4.2.1.1, and 5.x before 5.0.1 has…
CVE-2021-43082 — Critical (CVSS 9.8): Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') vulnerability in the stats-over-http plugin of…
CVE-2021-35474 — Critical (CVSS 9.8): Stack-based Buffer Overflow vulnerability in cachekey plugin of Apache Traffic Server. This issue affects Apache…
CVE-2020-1944 — Critical (CVSS 9.8): There is a vulnerability in Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5 with a smuggling…
CVE-2019-17565 — Critical (CVSS 9.8): There is a vulnerability in Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5 with a smuggling…
CVE-2019-17559 — Critical (CVSS 9.8): There is a vulnerability in Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.8, and 8.0.0 to 8.0.5 with a smuggling…

All CVEs affecting Apache Traffic Server →

Other CWE-287 (Improper Authentication) vulnerabilities

CVE-2026-45480 — Critical (CVSS 10.0): Improper authentication in Azure Active Directory allows an unauthorized attacker to elevate privileges over a network.
CVE-2026-46389 — Critical (CVSS 10.0): UDS Identity Config builds the Keycloak configuration image (realm, plugins, theme, truststore, JARs) consumed by UDS…
CVE-2026-10611 — Critical (CVSS 10.0): An authentication bypass vulnerability exists in MISP when LDAP mixed authentication is enabled with OTP enforcement.…
CVE-2026-47280 — Critical (CVSS 10.0): Improper authentication in Azure Resource Manager (ARM) allows an unauthorized attacker to elevate privileges over a…
CVE-2026-42822 — Critical (CVSS 10.0): Improper authentication in Azure Local Disconnected Operations allows an unauthorized attacker to elevate privileges…
CVE-2026-20182 — Critical (CVSS 10.0): May 2026: This security advisory provides the details and fix information for a vulnerability that was discovered and…

Browse all CWE-287 (Improper Authentication) vulnerabilities →