CVE-2021-21277 | Angular Expressions - Remote Code Execution

angular-expressions is "angular's nicest part extracted as a standalone module for the browser and node". In angular-expressions before version 1.1.2 there is a vulnerability which allows Remote Code Execution if you call "expressions.compile(userControlledInput)" where "userControlledInput" is text that comes from user input. The security of the package could be bypassed by using a more complex payload, using a ".constructor.constructor" technique. In terms of impact: If running angular-expressions in the browser, an attacker could run any browser script when the application code calls expressions.compile(userControlledInput). If running angular-expressions on the server, an attacker could run any Javascript expression, thus gaining Remote Code Execution. This is fixed in version 1.1.2 of angular-expressions A temporary workaround might be either to disable user-controlled input that will be fed into angular-expressions in your application or allow only following characters in the userControlledInput.

Published: 2021-02-01 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21277 is rated High Risk (65.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.73%). EPSS rose +2.40% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-21277

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.33% 2.73% +2.40%
2 2026-01-03 0.25% 0.33% +0.08%
3 2025-11-21 — 0.25% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21277

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.1 4.7 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2021-21277

GitHub Security Advisory for CVE-2021-21277

GHSA-j6px-jwvv-vpwq · Severity: high · Ecosystem: npm — Angular Expressions - Remote Code Execution

Affected software / configurations for CVE-2021-21277

Vendor Product Version Raw CPE
peerigon angular-expressions < 1.1.2 cpe:2.3:a:peerigon:angular-expressions:*:*:*:*:*:node.js:*:*

References for CVE-2021-21277

cvelogic Threat Intelligence