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🛡️ JLSEC-2026-106 — deno-jll

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. By using ANSI escape sequences and a race between libc::tcflush(0, libc::TCIFLUSH) and reading standard input, it's possible to manipulate the permission prompt and force it to allow an unsafe action regardless of the user input. Some ANSI escape sequences act as a info request to the master terminal emulator and the terminal emulator sends back the reply in the PTY channel. standard streams also use this channel to send and get data. For example the \033[6n sequence requests the current cursor position. These sequences allow us to append data to the standard input of Deno. This vulnerability allows an attacker to bypass Deno permission policy. This vulnerability is fixed in 1.42.2.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is high, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity high, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: High — the attacker first has to win a race, learn a secret or otherwise prepare the target.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: High — total loss, or loss the attacker controls.
  • Availability impact: None.

Affected software

JLSEC-2026-106 is recorded against 1 package.

  • deno-jll

Timeline and source

Published on 14 April 2026 and last revised on 18 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)

Other advisories for this package

deno-jll has other advisories on record. If you are patching this one, these are worth checking on the same host:

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-04-14
Updated 2026-08-20
Modified 2026-07-18
Fix URL N/A

Affected Packages

Software From version Fixed in
deno-jll — —

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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