CVE-2025-48888VulnerabilityPublished 4 Jun 2025

CVE-2025-48888: denoland deno · Incorrect Authorization

Affects denoland denoSource CVE Database V5

Not known to be exploited · CVSS 5.5 Medium · fixed in 2.3.2 : update denoland deno when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 4.0 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 2.3.2, 2.2.13, 2.1.13

CVSS: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:P

Base metrics

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: None
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: None
Subsequent system integrity: None
Subsequent system availability: None

Threat metrics

Exploit Maturity: POC

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: None: There is no loss of confidentiality within the Subsequent System or all confidentiality impact is constrained to the Vulnerable System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.
Exploit Maturity: POC: Based on threat intelligence sources each of the following must apply: · Proof-of-concept is publicly available · No knowledge of reported attempts to exploit this vulnerability · No knowledge of publicly available solutions used to simplify attempts to exploit the vulnerability

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 4 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade denoland/deno to 2.3.2, 2.2.13 or 2.1.13.

Affected software

Product	Affected	Fixed in
GitHubdenoland/deno`pkg:github/denoland/deno`Other threats	Affected <2.1.13 <2.2.13 <2.3.2 =1.41.3	Fixed in 2.1.13 2.2.13 2.3.2

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate this vulnerability effectively, European organizations should: 1) Immediately upgrade all Deno runtimes to versions 2.1.13, 2.2.13, or 2.3.2 where the issue is patched. 2) Audit existing Deno scripts and deployment pipelines to ensure that permission flags are not set in conflicting or nonsensical combinations, particularly avoiding simultaneous use of `--allow-*` and `--deny-*` flags for the same permission. 3) Implement strict code review and deployment policies to prevent unvetted or user-supplied permission flags from being used in production environments. 4) Employ runtime monitoring and logging to detect unusual permission flag usage or unexpected file access patterns during Deno script execution. 5) Where possible, isolate Deno execution environments using containerization or sandboxing to limit the blast radius of any potential exploitation. 6) Educate developers and DevOps teams about the correct usage of Deno permission flags and the risks of improper authorization configurations. These steps go beyond generic patching advice by focusing on operational controls and secure configuration management tailored to this specific vulnerability.

Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime. Starting in version 1.41.3 and prior to versions 2.1.13, 2.2.13, and 2.3.2, `deno run --allow-read --deny-read main.ts` results in allowed, even though 'deny' should be stronger. The result is the same with all global unary permissions given as `--allow-* --deny-*`. This only affects a nonsensical combination of flags, so there shouldn't be a real impact on the userbase. Users may upgrade to version 2.1.13, 2.2.13, or 2.3.2 to receive a patch.

Impact

For European organizations, the impact of this vulnerability is moderate but context-dependent. Deno is increasingly adopted for server-side scripting, automation, and microservices development due to its modern runtime capabilities. If an attacker can exploit this incorrect authorization flaw, they could potentially bypass intended permission restrictions, leading to unauthorized file reads or other privileged operations. This could expose sensitive data or internal configuration files, undermining confidentiality. However, the exploit requires the attacker to invoke Deno with a specific, conflicting set of permission flags, which is an uncommon and nonsensical usage pattern, reducing the likelihood of accidental or widespread exploitation. Still, in environments where Deno scripts are run with dynamic or user-controlled flags, or in multi-tenant systems, this vulnerability could be leveraged to escalate access. The lack of required authentication or user interaction increases the theoretical risk. European organizations relying on Deno for critical infrastructure or sensitive data processing should consider this vulnerability seriously, especially in sectors like finance, government, and technology where data confidentiality and integrity are paramount.

CWE-863Incorrect Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #17OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Jul 2025, 18:55 UTC

WeaknessesCWE-863

Technical details

References

Community reviews

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