How severe is CVE-2020-9494?

CVE-2020-9494 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-2020-9494 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-9494?

CVE-2020-9494 primarily affects Apache Traffic Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-9494?

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-2020-9494 published?

CVE-2020-9494 was published on 2020-06-24 and last updated on 2026-06-17.

CVE-2020-9494

CVE-2020-9494 is a high-severity vulnerability in Apache Traffic Server 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-770.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-770
Affected product: Apache Traffic Server
Published: 2020-06-24
Last modified: 2026-06-17

Description

Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, and 8.0.0 to 8.0.7 is vulnerable to certain types of HTTP/2 HEADERS frames that can cause the server to allocate a large amount of memory and spin the thread.

Frequently asked questions

What is CVE-2020-9494?: Apache Traffic Server 6.0.0 to 6.2.3, 7.0.0 to 7.1.10, and 8.0.0 to 8.0.7 is vulnerable to certain types of HTTP/2 HEADERS frames that can cause the server to allocate a large amount of memory and spin the thread.
How severe is CVE-2020-9494?: CVE-2020-9494 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-2020-9494 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-9494?: CVE-2020-9494 primarily affects Apache Traffic Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-9494?: 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-2020-9494 published?: CVE-2020-9494 was published on 2020-06-24 and last updated on 2026-06-17.

References

Affected products (2)

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

More vulnerabilities in Apache Traffic Server

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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…

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