CVE-2024-34346
Deno contains a permission escalation via open of privileged files with missing `--deny` flag
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
Attack profile
How easy it is to exploit
- Attack vector
- Adjacent network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
8.5
Deno contains a permission escalation via open of privileged files with missing `--deny` flag
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
- Record
CVE-2024-34346- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
EUVDEUVD-2024-1344
8.5
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
- Record
EUVD-2024-1344- CVSS 3.1
- 8.5 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-23rx-c3g5-hv9w
8.4
Deno permission escalation vulnerability via open of privileged files with missing `--deny` flag
The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all.
Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox.
Impact
Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations.
Patches
Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
Workarounds
The security sandbox in previous versions of Deno allows for denial of access to these files, but it requires an explicit addition of deny flags: --deny-read=/dev --deny-read=/sys --deny-read=/proc --deny-read=/etc --deny-write=/dev --deny-write=/sys --deny-write=/proc --deny-write=/etc. Note that symlinks in allowed locations may defeat this protection in earlier versions of Deno.
Reporters
This vulnerability was reported by a number of analysts. Thanks to [email protected], [email protected], @leesh3288, and @cristianstaicu for their reports and analysis.
- Record
GHSA-23rx-c3g5-hv9w- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
NVD
8.4
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
- Record
CVE-2024-34346- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
OSV
8.4
Deno contains a permission escalation via open of privileged files with missing `--deny` flag
Deno is a JavaScript, TypeScript, and WebAssembly runtime with secure defaults. The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all. Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox. Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations. Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
- Record
CVE-2024-34346- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVGHSA-23rx-c3g5-hv9w
8.4
Deno permission escalation vulnerability via open of privileged files with missing `--deny` flag
The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all.
Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox.
Impact
Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations.
Patches
Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
Workarounds
The security sandbox in previous versions of Deno allows for denial of access to these files, but it requires an explicit addition of deny flags: --deny-read=/dev --deny-read=/sys --deny-read=/proc --deny-read=/etc --deny-write=/dev --deny-write=/sys --deny-write=/proc --deny-write=/etc. Note that symlinks in allowed locations may defeat this protection in earlier versions of Deno.
Reporters
This vulnerability was reported by a number of analysts. Thanks to [email protected], [email protected], @leesh3288, and @cristianstaicu for their reports and analysis.
- Record
GHSA-23rx-c3g5-hv9w- CVSS 3.1
- 8.4 High
CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-863
- Updated
- 2026-11-02
OSVJLSEC-2026-107
9.0
Deno permission escalation vulnerability via open of privileged files with missing `--deny` flag
The Deno sandbox may be unexpectedly weakened by allowing file read/write access to privileged files in various locations on Unix and Windows platforms. For example, reading /proc/self/environ may provide access equivalent to --allow-env, and writing /proc/self/mem may provide access equivalent to --allow-all.
Users who grant read and write access to the entire filesystem may not realize that these access to these files may have additional, unintended consequences. The documentation did not reflect that this practice should be undertaken to increase the strength of the security sandbox.
Impact
Users who run code with --allow-read or --allow-write may unexpectedly end up granting additional permissions via file-system operations.
Patches
Deno 1.43 and above require explicit --allow-all access to read or write /etc, /dev on unix platform (as well as /proc and /sys on linux platforms), and any path starting with \\ on Windows.
Workarounds
The security sandbox in previous versions of Deno allows for denial of access to these files, but it requires an explicit addition of deny flags: --deny-read=/dev --deny-read=/sys --deny-read=/proc --deny-read=/etc --deny-write=/dev --deny-write=/sys --deny-write=/proc --deny-write=/etc. Note that symlinks in allowed locations may defeat this protection in earlier versions of Deno.
Reporters
This vulnerability was reported by a number of analysts. Thanks to [email protected], [email protected], @leesh3288, and @cristianstaicu for their reports and analysis.
- Record
JLSEC-2026-107- CVSS 3.1
- 9.0 Critical
CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
History
| Recorded | Changed | Sources |
|---|---|---|
| published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-34346 is a high vulnerability (CVSS 8.5) in Deno, published May 7, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 30th percentile. Fixed in deno 1.43.1.