How severe is CVE-2022-34037?

CVE-2022-34037 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-2022-34037 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2022-34037?

CVE-2022-34037 affects Caddyserver Caddy. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2022-34037?

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-2022-34037 published?

CVE-2022-34037 was published on 2022-07-22 and last updated on 2026-06-17.

CVE-2022-34037

CVE-2022-34037 is a high-severity vulnerability in Caddyserver Caddy 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-125.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 1% (58th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Caddyserver Caddy
Published: 2022-07-22
Last modified: 2026-06-17

Description

An out-of-bounds read in the rewrite function at /modules/caddyhttp/rewrite/rewrite.go in Caddy v2.5.1 allows attackers to cause a Denial of Service (DoS) via a crafted URI. Note: This has been disputed as a bug, not a security vulnerability, in the Caddy web server that emerged when an administrator's bad configuration containing a malformed request URI caused the server to return an empty reply instead of a valid HTTP response to the client.

Frequently asked questions

What is CVE-2022-34037?: An out-of-bounds read in the rewrite function at /modules/caddyhttp/rewrite/rewrite.go in Caddy v2.5.1 allows attackers to cause a Denial of Service (DoS) via a crafted URI. Note: This has been disputed as a bug, not a security vulnerability, in the Caddy web server that emerged when an administrator's bad configuration containing a malformed request URI caused the server to return an empty reply instead of a valid HTTP response to the client.
How severe is CVE-2022-34037?: CVE-2022-34037 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-2022-34037 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (58th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2022-34037?: CVE-2022-34037 affects Caddyserver Caddy. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2022-34037?: 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-2022-34037 published?: CVE-2022-34037 was published on 2022-07-22 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:caddyserver:caddy:2.5.1:*:*:*:*:*:*:*

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