CVE-2026-55602: chimurai http-proxy-middleware Improper Input Validation
CVSS: 8.6v3.1HighAnalyzed
AliasesCGA-27g6-2699-pc6rCGA-2w36-6h43-x3prCGA-392v-pcqv-7prcCGA-3c2q-87pf-xhjcCGA-4898-3h99-7fc5CGA-5328-wxj2-q3fcCGA-5fqj-2g8q-rw7pCGA-63r6-7h9f-frm8CGA-796w-jqh4-f3rcCGA-858f-gjp8-wgm9CGA-8gg4-frx5-pf3fCGA-965w-9m4x-hm4pCGA-99rq-38wg-qg57CGA-9gfv-whwr-rpvmCGA-c7rr-qx55-m436CGA-f892-84fv-6rjfCGA-hj29-8cfp-x2fhCGA-hqg3-j77f-px8cCGA-hr49-jxx9-53xxCGA-j57r-j283-27g2CGA-jfqf-5m9q-83h2CGA-jw55-pmc8-hqr5CGA-mg9w-qr6p-prj2CGA-p5p3-4x3v-fpf6CGA-p739-rwmc-xv45CGA-ppq6-x3xx-mmxgCGA-qjrm-6m75-4q2wCGA-vq72-frqw-wfjwCGA-wvf3-r388-q235CGA-xp84-v4cj-29m4GHSA-64mm-vxmg-q3vjCGA-25j2-ww6h-54hvCGA-2wpp-3qvf-76h3CGA-3wcc-j78q-v59rCGA-4cr7-62hr-7xqmCGA-4g4c-7p6w-rpr8CGA-525x-rjpv-xr8cCGA-53v4-x5pv-g6hwCGA-57wv-qg6j-99xcCGA-5c88-2f9c-9wrgCGA-6vc6-9w6r-pcc6CGA-7229-92pw-76hvCGA-7v9q-fj6g-gxj4CGA-7xq8-gcpm-g9gfCGA-852h-24gv-728fCGA-9f3q-xg9q-gm8pCGA-9rhp-wv8q-88hmCGA-c2xw-crr5-gj2rCGA-cgvq-3mpj-x99qCGA-f25p-f4mf-3wpcCGA-ffvq-5f59-7288CGA-fpvp-c74q-q4q6CGA-g472-63m9-r7vjCGA-g52c-6gc8-x3mcCGA-g965-q5xg-7qg7CGA-gg64-ww2c-3jfcCGA-gh9c-6qpj-jxwqCGA-gj7g-j278-9xc9CGA-gmv3-p8p6-hp97CGA-gv93-jgpc-wf87CGA-h2ch-3xq9-65q6CGA-h6qc-gfg9-xqm5CGA-hh3r-cmjr-g4w7CGA-hwr8-6mj7-6j9mCGA-j3cp-f87j-54h3CGA-j6hr-2hrp-vqqjCGA-m4h3-748q-m2q6CGA-mfx2-ppg4-mf8qCGA-mx64-fpr2-r7qwCGA-p8fg-rq78-p4hcCGA-p9j4-j9qp-679fCGA-pfm5-94xm-cm46CGA-qp8f-839r-9h5vCGA-qrf4-6r52-hrvqCGA-qwqm-j892-g6wcCGA-r9g2-953j-c48rCGA-r9g5-p9fv-pf52CGA-vc5x-mf52-3rj4CGA-vgm8-vxxw-php2CGA-w47v-h2gr-rvwfCGA-w92g-6c3x-qcgxCGA-wm84-r32r-7w69CGA-x2v6-7fj6-q473CGA-x9j8-q5v7-8qr5CGA-xg9g-g4gg-rxmxCGA-xmp8-p6xc-gvmhCGA-xpg9-5cx9-xcj4
Published 22-06-2026Last modified 23-06-2026
Vulnerability summary
CVE-2026-55602 is a high (CVSS 8.6) Improper Input Validation vulnerability in chimurai http-proxy-middleware. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.4% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
8.6/10
010
High · v3.1 (NVD)EPSS score
0.38%
0%100%
Low · +0.01 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github
Advisory lineage
Upstream 0 · Downstream 3 · Related 4Timeline
- 22-06-2026PublishedVulnerability first disclosed.
- 23-06-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
6 scores · 5 sources · 2 versionsMedium 6.9Preferred score · CVE.org (CNA)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:NSourcesAll 5 agree
- OSV · WolfiEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- OSV · NpmEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- OSV · ChainguardEcosystem advisory · calculated6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N
- NVDNIST6.9MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
High 8.6Preferred score · NVD (NIST)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:NSourcesSingle source
EPSS trend
Probability
0.38%
Chance of exploitation in the next 30 days
Percentile
30%
Versus all other CVEs
30-day change
+0.01 pp
From 0.37% on 21-09-2026
21-09-202621-10-2026
EPSS score0.38%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundHttp Proxy Middleware
Maturity: poc
Weaknesses
CWE · root cause- CWE-20Improper Input ValidationThe product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
- CWE-187Partial String ComparisonThe product performs a comparison that only examines a portion of a factor before determining whether there is a match, such as a substring, leading to resultant weaknesses.
Affected systems
Chainguard42 products
- arangodb-3.11< 3.11.14.5-r20
- arangodb-3.12< 3.12.11-r0
- argo-workflows-ui-3.6< 3.6.19-r7
- argo-workflows-ui-3.7< 3.7.15-r1
- argo-workflows-ui-4.0< 4.0.11-r0 | < 4.0.6-r1
Wolfi15 products
- argo-workflows-ui-3.7< 3.7.15-r1
- argo-workflows-ui-4.0< 4.0.11-r0 | < 4.0.6-r1
- katib-earlystopping< 0.19.0-r31
- katib-suggestion-goptuna-compatAll versions (No fix recorded)
- katib-suggestion-hyperband< 0.19.0-r31
Chimurai1 product
- http-proxy-middleware≥ 0.16.0, < 2.0.10 | ≥ 3.0.0, < 3.0.6 | ≥ 4.0.0, < 4.1.0
Npm1 product
- http-proxy-middleware≥ 3.0.0, < 3.0.6 | ≥ 4.0.0, < 4.1.0 | ≥ 0.16.0, < 2.0.10
4 vendors · 59 products
References
4 links- github.com/chimurai/http-proxy-middleware/security/advisories/GHSA-64mm-vxmg-q3vjX Refsource CONFIRMAdvisoryWEBExploitVendor Advisory
