VulnerabilityPublished 20 Jan 2026Updated 27 Oct 2026

CVE-2026-23950: node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3

Affects node-tarSource GCVE Database

Authoritative record:CVE-2026-23950· High 8.8

Not known to be exploited · CVSS 8.8 High.

Data as of 27 Oct 2026, 06:42 UTC

CVSS 3.1 base score

8.8High

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

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: Required
Scope: Changed
Confidentiality: Low
Integrity: High
Availability: Low

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

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, 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: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: Required: Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited.
Scope: Changed: An exploited vulnerability can affect resources beyond the security scope managed by the security authority of the vulnerable component. In this case, the vulnerable component and the impacted component are different and managed by different security authorities.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 20 Jan 2026
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 26 Oct 2026.

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 or the CVSS exploit maturity 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

Affected software

Product	Affected	Fixed in
Ubuntu 26.10node-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=stonking`Other threats	Affected =6.2.1+ds1+~cs6.1.13-10 =7.5.22+~4.0.1-1	Fixed in–
Ubuntu 26.04 LTSnode-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=resolute`Other threats	Affected 6.2.1+~cs7.0.8-1 – 6.2.1+ds1+~cs6.1.13-10 4 affected builds	Fixed in–
Ubuntu 25.10node-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=questing`Other threats	Affected =6.2.1+~cs7.0.8-1	Fixed in–
Ubuntu 24.04 LTSnode-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=noble`Other threats	Affected =6.1.13+~cs7.0.5-1 =6.1.13+~cs7.0.5-3	Fixed in–
Ubuntu 22.04 LTSnode-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=jammy`Other threats	Affected =6.1.7+~cs11.3.10-1 =6.1.11+~cs11.3.10-1 =6.1.11+ds1+~cs6.0.6-1	Fixed in–
Ubuntu Pro 20.04 LTSnode-tar`pkg:deb/ubuntu/node-tar?arch=source&distro=esm-apps/focal`Other threats	Affected =4.4.10+ds1-2 =4.4.10+ds1-2ubuntu1 =4.4.10+ds1-2ubuntu1+esm1	Fixed in–

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

Description

node-tar,a Tar for Node.js, has a race condition vulnerability in versions up to and including 7.5.3. This is due to an incomplete handling of Unicode path collisions in the `path-reservations` system. On case-insensitive or normalization-insensitive filesystems (such as macOS APFS, In which it has been tested), the library fails to lock colliding paths (e.g., `ß` and `ss`), allowing them to be processed in parallel. This bypasses the library's internal concurrency safeguards and permits Symlink Poisoning attacks via race conditions. The library uses a `PathReservations` system to ensure that metadata checks and file operations for the same path are serialized. This prevents race conditions where one entry might clobber another concurrently. This is a Race Condition which enables Arbitrary File Overwrite. This vulnerability affects users and systems using node-tar on macOS (APFS/HFS+). Because of using `NFD` Unicode normalization (in which `ß` and `ss` are different), conflicting paths do not have their order properly preserved under filesystems that ignore Unicode normalization (e.g., APFS (in which `ß` causes an inode collision with `ss`)). This enables an attacker to circumvent internal parallelization locks (`PathReservations`) using conflicting filenames within a malicious tar archive. The patch in version 7.5.4 updates `path-reservations.js` to use a normalization form that matches the target filesystem's behavior (e.g., `NFKD`), followed by first `toLocaleLowerCase('en')` and then `toLocaleUpperCase('en')`. As a workaround, users who cannot upgrade promptly, and who are programmatically using `node-tar` to extract arbitrary tarball data should filter out all `SymbolicLink` entries (as npm does) to defend against arbitrary file writes via this file system entry name collision issue.

References

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