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CVE-2024-27936

Deno interactive permission prompt spoofing via improper ANSI stripping

8.8 HighFix available

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to version 1.41.0 of the deno library, maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents. Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences. Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user. Version 1.41.0 of the deno library contains a patch for the issue.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
Required

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.94%Up 0.9 points since Mar 7, 2024
90%50%10%1%

What each source reports

CVE List Score used 8.8

Deno interactive permission prompt spoofing via improper ANSI stripping

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to version 1.41.0 of the deno library, maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents. Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences. Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user. Version 1.41.0 of the deno library contains a patch for the issue.

Record
CVE-2024-27936
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-150
Updated
2026-11-02
EUVDEUVD-2024-0957 8.8

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to version 1.41.0 of the deno library, maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents. Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences. Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user. Version 1.41.0 of the deno library contains a patch for the issue.

Record
EUVD-2024-0957
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated
2026-11-03
GitHub AdvisoriesGHSA-m4pq-fv2w-6hrw 8.8

Deno's deno_runtime vulnerable to interactive permission prompt spoofing via improper ANSI stripping

Summary

A maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents.

Details

In the patch for CVE-2023-28446, Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences.

For example, requesting the read permission with /tmp/hello\u001b[/../../etc/hosts as a path will display the /tmp/hellotc/hosts in the permission prompt, but the actual permission given to the program is /tmp/hello\u001b[/../../etc/hosts, which is /etc/hosts after the normalization.

This difference allows a malicious Deno program to spoof the contents of the permission prompt.

PoC

Run the following JavaScript and observe that /tmp/hellotc/hosts is displayed in the permission prompt instead of /etc/hosts, although Deno gives access to /etc/hosts.

const permission = { name: "read", path: "/tmp/hello\u001b[/../../etc/hosts" };
await Deno.permissions.request(permission);
console.log(await Deno.readTextFile("/etc/hosts"));

Expected prompt

┌ ⚠️  Deno requests read access to "/etc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Actual prompt

┌ ⚠️  Deno requests read access to "/tmp/hellotc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Impact

Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user.

Record
GHSA-m4pq-fv2w-6hrw
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-150
Updated
2026-11-02
NVD 8.8

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to version 1.41.0 of the deno library, maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents. Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences. Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user. Version 1.41.0 of the deno library contains a patch for the issue.

Record
CVE-2024-27936
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Weakness
CWE-150
Updated
2026-11-02
OSV 8.8

Deno interactive permission prompt spoofing via improper ANSI stripping

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. Starting in version 1.32.1 and prior to version 1.41.0 of the deno library, maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents. Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences. Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user. Version 1.41.0 of the deno library contains a patch for the issue.

Record
CVE-2024-27936
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-150
Updated
2026-11-02
OSVGHSA-m4pq-fv2w-6hrw 8.8

Deno's deno_runtime vulnerable to interactive permission prompt spoofing via improper ANSI stripping

Summary

A maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents.

Details

In the patch for CVE-2023-28446, Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences.

For example, requesting the read permission with /tmp/hello\u001b[/../../etc/hosts as a path will display the /tmp/hellotc/hosts in the permission prompt, but the actual permission given to the program is /tmp/hello\u001b[/../../etc/hosts, which is /etc/hosts after the normalization.

This difference allows a malicious Deno program to spoof the contents of the permission prompt.

PoC

Run the following JavaScript and observe that /tmp/hellotc/hosts is displayed in the permission prompt instead of /etc/hosts, although Deno gives access to /etc/hosts.

const permission = { name: "read", path: "/tmp/hello\u001b[/../../etc/hosts" };
await Deno.permissions.request(permission);
console.log(await Deno.readTextFile("/etc/hosts"));

Expected prompt

┌ ⚠️  Deno requests read access to "/etc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Actual prompt

┌ ⚠️  Deno requests read access to "/tmp/hellotc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Impact

Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user.

Record
GHSA-m4pq-fv2w-6hrw
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-150
Updated
2026-11-02
OSVJLSEC-2026-105 6.5

Deno's `deno_runtime` vulnerable to interactive permission prompt spoofing via improper ANSI stripping

Summary

A maliciously crafted permission request can show the spoofed permission prompt by inserting a broken ANSI escape sequence into the request contents.

Details

In the patch for CVE-2023-28446, Deno is stripping any ANSI escape sequences from the permission prompt, but permissions given to the program are based on the contents that contain the ANSI escape sequences.

For example, requesting the read permission with /tmp/hello\u001b[/../../etc/hosts as a path will display the /tmp/hellotc/hosts in the permission prompt, but the actual permission given to the program is /tmp/hello\u001b[/../../etc/hosts, which is /etc/hosts after the normalization.

This difference allows a malicious Deno program to spoof the contents of the permission prompt.

PoC

Run the following JavaScript and observe that /tmp/hellotc/hosts is displayed in the permission prompt instead of /etc/hosts, although Deno gives access to /etc/hosts.

const permission = { name: "read", path: "/tmp/hello\u001b[/../../etc/hosts" };
await Deno.permissions.request(permission);
console.log(await Deno.readTextFile("/etc/hosts"));

Expected prompt

┌ ⚠️  Deno requests read access to "/etc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Actual prompt

┌ ⚠️  Deno requests read access to "/tmp/hellotc/hosts".
├ Requested by `Deno.permissions.query()` API
├ Run again with --allow-read to bypass this prompt.
└ Allow? [y/n/A] (y = yes, allow; n = no, deny; A = allow all read permissions) >

Impact

Any Deno program can spoof the content of the interactive permission prompt by inserting a broken ANSI code, which allows a malicious Deno program to display the wrong file path or program name to the user.

Record
JLSEC-2026-105
CVSS 3.1
6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
deno
crates.io
1.32.1 up to 1.41.0
1.41.0
deno_runtime
crates.io
0.103.0 up to 0.147.0
0.147.0
Deno_jll
Julia
1.33.4+0 up to 2.0.0+0
2.0.0+0

History

History
RecordedChangedSources
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2024-27936 is a high vulnerability (CVSS 8.8) in Deno, published March 5, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.94%, the 61st percentile. Fixed in deno 1.41.0.

References

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