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Fencer Vulns
critical 10.0

CVE-2020-26282 json

Template Injection in BrowserUp Proxy

published 2020-12-24 5 y ago modified 2026-09-10 1 mo ago also GHSA-wmfg-55f9-j8hq , EUVD-2020-1509

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 92%
public exploits
0
none known

Summary

BrowserUp Proxy allows you to manipulate HTTP requests and responses, capture HTTP content, and export performance data as a HAR file. BrowserUp Proxy works well as a standalone proxy server, but it is especially useful when embedded in Selenium tests. A Server-Side Template Injection was identified in BrowserUp Proxy enabling attackers to inject arbitrary Java EL expressions, leading to unauthenticated Remote Code Execution (RCE) vulnerability. This has been patched in version 2.1.2.

Patch / fix

  • maven com.browserup:browserup-proxy 2.1.2
  • browserup browserup_proxy 2.1.2

Exploit prediction

4.83% chance of exploitation in the next 30 days, higher than 92% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • securitylab.github.com https://securitylab.github.com/research/bean-validation-RCE referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N
NVD 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
GitHub 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

Affected packages

ecosystem package affected fixed in
maven com.browserup:browserup-proxy
<2.1.2
2.1.2

Affected products

  • browserup browserup-proxy

Classification

Weakness
  • CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.