How severe is CVE-2026-55602?

CVE-2026-55602 has a CVSS 3.x base score of 8.6, 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 high, and availability none.

Is CVE-2026-55602 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-55602?

CVE-2026-55602 affects Chimurai Http-proxy-middleware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-55602?

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.

Does CVE-2026-55602 have an EU (EUVD) identifier?

Yes. CVE-2026-55602 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38300.

When was CVE-2026-55602 published?

CVE-2026-55602 was published on 2026-06-22 and last updated on 2026-06-26.

CVE-2026-55602

CVE-2026-55602 is a high-severity vulnerability in Chimurai Http-proxy-middleware with a CVSS 3.x base score of 8.6. 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-20.

Key facts

Severity: High (CVSS 3.x base score 8.6)
CVSS v4: 6.9
EPSS exploit prediction: 0% (26th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-38300
Weakness: CWE-20
Affected product: Chimurai Http-proxy-middleware
Published: 2026-06-22
Last modified: 2026-06-26

Description

http-proxy-middleware is node.js http-proxy middleware. From 0.16.0 until 2.0.10, 3.0.6, and 4.1.0, http-proxy-middleware documents router proxy-table entries as host, path, or host+path selectors, but the host+path implementation uses unanchored substring matching on attacker-controlled request metadata. As a result, a crafted Host header that is only a superstring match for a configured host+path key can still route a request to an unintended backend. This vulnerability is fixed in 2.0.10, 3.0.6, and 4.1.0.

Frequently asked questions

What is CVE-2026-55602?: http-proxy-middleware is node.js http-proxy middleware. From 0.16.0 until 2.0.10, 3.0.6, and 4.1.0, http-proxy-middleware documents router proxy-table entries as host, path, or host+path selectors, but the host+path implementation uses unanchored substring matching on attacker-controlled request metadata. As a result, a crafted Host header that is only a superstring match for a configured host+path key can still route a request to an unintended backend. This vulnerability is fixed in 2.0.10, 3.0.6, and 4.1.0.
How severe is CVE-2026-55602?: CVE-2026-55602 has a CVSS 3.x base score of 8.6, 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 high, and availability none.
Is CVE-2026-55602 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (26th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-55602?: CVE-2026-55602 affects Chimurai Http-proxy-middleware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-55602?: 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.
Does CVE-2026-55602 have an EU (EUVD) identifier?: Yes. CVE-2026-55602 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38300.
When was CVE-2026-55602 published?: CVE-2026-55602 was published on 2026-06-22 and last updated on 2026-06-26.

References

https://github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-64mm-vxmg-q3vj

Affected products (1)

cpe:2.3:a:chimurai:http-proxy-middleware:*:*:*:*:*:*:*:*

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