VulnerabilityPublished 28 Oct 2026

CVE-2026-115887: graphql-scalars PhoneNumber scalar is vulnerable to regular expression denial of service

Affects graphql-scalarsSource GCVE Database

Authoritative record:CVE-2026-115887· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 2.0.1 soon.

Data as of 28 Oct 2026, 22:12 UTC

CVSS 3.1 base score

7.5High

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

Patch: Available – fixed in 2.0.1

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

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

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: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 23 Oct 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

Upgrade graphql-scalars to 2.0.1.

Affected software

Product	Affected	Fixed in
npmgraphql-scalars	Affected <2.0.1	Fixed in 2.0.1

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

Description

## Summary The regular expression behind `GraphQLPhoneNumber` since 1.24.1 backtracks exponentially. A string made of a run of digits followed by one character that makes the match fail (for example `"1".repeat(30) + "x"`) blocks the JavaScript thread for seconds, and every additional digit doubles the time. graphql-js calls `parseLiteral` while *validating* a document and `parseValue` while coercing variables, so the regex runs for every request that merely contains such a value in a `PhoneNumber` position, before execution and before any authentication or authorization step of the server. One small unauthenticated request is enough to stall a server process. ## Affected versions - `graphql-scalars` >= 1.24.1, <= 2.0.0 (2.0.0 is the current `latest`; the default branch still has the same pattern). - Not affected: 1.24.0 and the earlier versions I checked (1.22.4, 1.23.0), which use the linear `/^\+[1-9]\d{6,14}$/`. - Introduced by #2719 (c7f58da16, "PhoneNumber scalar is not fully compatible with E.164 format so updated regex to support phone number with extension"), released as 1.24.1 on 2025-01-29. The payload was ran against 1.22.4, 1.23.0, 1.24.0, 1.24.1, 1.24.2, 1.25.0, 1.26.0 and 2.0.0: the first three reject it instantly, the other five show the exponential growth. ## Root cause `src/scalars/PhoneNumber.ts`: ```js const PHONE_NUMBER_REGEX = /^\+?\d{1,3}(\-|\x20)?$?\d+$?((\-|\x20)?\d+)+$/; ``` In `\d+\)?((\-|\x20)?\d+)+$` the separator is optional, so a run of n digits can be split across the inner `\d+` and the outer `+` iterations in a number of ways that is exponential in n. When the overall match fails, for instance on a trailing non-digit, the engine tries all of them. ## Proof of concept 1. The scalar alone (`npm i graphql graphql-scalars@2.0.0`): ```js import { GraphQLPhoneNumber } from 'graphql-scalars'; for (const ok of ['+41791234567', '079 123 45 67', '+1 (123) 456-7890', 'nope']) { try { GraphQLPhoneNumber.parseValue(ok); } catch {} } for (const digits of [24, 26, 28, 30]) { const start = performance.now(); try { GraphQLPhoneNumber.parseValue('1'.repeat(digits) + 'x'); } catch {} console.log(`${digits} digits: ${((performance.now() - start) / 1000).toFixed(2)} s`); } ``` Measured warm, i.e. after ordinary inputs have been validated like in a running server: | digits | Node 22.19.0 | Node 26.10.0 | |-------:|-------------:|-------------:| | 24 | 0.10 s | 0.07 s | | 26 | 0.41 s | 0.29 s | | 28 | 1.63 s | 1.14 s | | 30 | 6.59 s | 4.62 s | The time doubles with every digit. The first execution of the regex in a fresh process is about 5x slower because V8 interprets a regexp on its first run (Node 22.19.0, 28 digits: 7.8 s). 2. Through graphql-js, no server and no authentication: a schema with a single `echo(phone: PhoneNumber)` field, 26 digits + `x`, Node 22.19.0, warm: | | literal (`parseLiteral`, validation) | variable (`parseValue`, coercion) | |---|---:|---:| | graphql 16.14.2 | 0.41 s | 0.43 s | | graphql 17.0.2 | 0.41 s | 0.83 s (evaluated twice) | 3. Also reproduced end to end against a GraphQL Yoga server: an anonymous HTTP request with a 27-digit value plus one invalid character stalled the whole process (a concurrent trivial `{ __typename }` request waited as long). A mutation that requires authentication was affected equally when called anonymously, because document validation runs before any authorization in resolvers or context. ## Impact Denial of service. Any GraphQL server that exposes `PhoneNumber` on an argument, an input object field or a variable can be stalled by a request of about 30 characters; roughly 40 characters would keep a process busy for hours (extrapolated from the doubling, not measured). `serialize` uses the same regex, so unvalidated stored values returned through a `PhoneNumber` field are affected too. The actual severity depends on the scalar being applied to untrusted input, which is the typical case. ## Suggested fix An equivalent pattern without ambiguous splits: ```js const PHONE_NUMBER_REGEX = /^\+?\d{1,3}[- ]?$?\d(?:\d*$)?(?:[- ]?\d)+$/; ``` It accepts exactly the same strings as the current one, so there is no behaviour change: with `N = (S?\d+)+ = (S?\d)+` a digit run is just repeated single-digit iterations, hence `\d+\)?N = \d(\d*\))?N`. Verification: - exhaustive comparison of old and new pattern on every string up to length 9 over `1 + - space ( ) x`: 47,079,208 strings (1,832 accepted), 0 differences; - every sequence of up to 6 tokens from `1 11 111 1111 11111 + - space ( ) x`: 1,948,717 strings (100,380 accepted), 0 differences; - adversarial inputs (digit runs plus a failing character, digit/space and digit/dash alternations, parenthesis variants) scale linearly: 1,000,000 characters take about 10 ms, where the current pattern needs 0.3 s for 26. Optionally also reject values above a sane length before matching; the grammar currently has no upper bound and E.164 allows at most 15 digits. Above roughly

CWE-1333Inefficient Regular Expression Complexity (opens in a new tab)
Base weaknessLikelihood of exploit: High
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Architecture and Design
Use regular expressions that do not support backtracking, e.g. by removing nested quantifiers.
System Configuration
Set backtracking limits in the configuration of the regular expression implementation, such as PHP's pcre.backtrack_limit. Also consider limits on execution time for the process.
Implementation
Do not use regular expressions with untrusted input. If regular expressions must be used, avoid using backtracking in the expression.
OWASP Cheat Sheets
File Upload (opens in a new tab)
OWASP ASVS 4.0.3
V12.1.1 (opens in a new tab)
Attack patterns
Regular Expression Exponential Blowup (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-1333

Technical details

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