CVE-2021-43557

mediumpriority · attend · 45EPSS 0.130 · 96 %ileexploit · PoCEURUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

1 exploit · PoC

Likely / severe?

13.0% (96th) EPSS

CVSS 5 · medium

Is it mine?

4 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

EPSS · scored 2026-10-27

The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5

v2.05mediumAV:N/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 3.9 · impact 3.6

v3.17.5highAV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · FSTEC (BDU) RU

v3.17.1highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Psecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-77USprimaryCWE-77US

exploits (1)

Public proof-of-concept and weaponised exploit code.

xvnpw/k8s-CVE-2021-43557-pocPoC for CVE-2021-43557PoC · poc_in_github

affected products (4)

Products and version ranges known to be affected.

Apache Software Foundation Apache APISIX1.5 → Apache APISIX 1.5*enisa_euvdEU
Apache Software Foundation APISIX≤ 2.10.2fstec_bduRU
apache apisix< 2.10.2nvdUScpe:2.3:a:apache:apisix:*:*:*:*:*:*:*:*
Bitnami apisix< 2.10.2osvUSpkg:bitnami/apisix

advisories (1)

Vendor and ecosystem advisories describing this.

BIT-apisix-2021-43557Path traversal in request_uri variable2024-03-06vendor · osvUS
The uri-block plugin in Apache APISIX before 2.10.2 uses $request_uri without verification. The $request_uri is the full original request URI without normalization. This makes it possible to construct a URI to bypass the block list on some occasions. For instance, when the block list contains "^/internal/", a URI like `//internal/` can be used to bypass it. Some other plugins also have the same issue. And it may affect the developer's custom plugin.

also known as (4)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd osv NVD CVE.org MITRE

published 2021-11-22modified 2026-06-17

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+4594 more

references (14)

External citations — patches, advisories, analysis.

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