CVE-2021-43557
This makes it possible to construct a URI to bypass the block list on some occasions.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 13.0%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.
Description
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 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 13.04% probability · 96th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-77
- Affected
- apache/apisix
- Source
- security@apache.org
EPSS 13.0% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://www.openwall.com/lists/oss-security/2021/11/22/1Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/11/22/2Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/11/23/1Exploit, Mailing List, Third Party Advisory
- https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h366mv7hExploit, Mailing List, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2021/11/22/1Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/11/22/2Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/11/23/1Exploit, Mailing List, Third Party Advisory
- https://lists.apache.org/thread/18jyd458ptocr31rnkjs71w4h366mv7hExploit, Mailing List, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.