VulnerabilityPublished 23 Oct 2026Updated 29 Oct 2026

CVE-2026-75508: GraphQL-core · Denial of service via comment tokens bypassing the parser's max_tokens limit

Affects motoSource GCVE Database

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Authoritative record:CVE-2026-75508· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade to 5.2.3_1 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

7.5High

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

Thin evidence

One scorer or none

CVSS scores by source
CNA (GitHub_M)	CVSS 3.1	7.5

EPSS: 0.5% chance of exploitation in 30 days – higher than 47% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.2.3_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 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 29 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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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 moto to 5.2.3_1.

Affected software

Product	Affected	Fixed in
Homebrewmoto`pkg:brew/moto`Other threats	Affected >=4.0.6 <5.2.3_1	Fixed in 5.2.3_1

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

AI-suggested

Upgrade GraphQL-core to version 3.2.12 or later, or 3.3.0rc1 or later, where the parser counts comment tokens towards the max_tokens limit, effectively fixing the vulnerability. If upgrading is not possible, apply a request body-size limit on the decompressed request body before parsing to prevent excessive memory usage. Even after upgrading, maintaining body-size limits is recommended as max_tokens limits token count but does not fully bound request cost.

Description

A denial of service vulnerability in GraphQL-core's parser allows comment tokens to bypass the max_tokens limit, leading to excessive memory allocation. The parser's max_tokens counter did not include comment tokens, enabling an attacker to craft documents with many comments that consume large amounts of memory without triggering the limit. This can cause memory exhaustion and potential worker process termination. The issue is fixed in versions 3.2.12 and 3.3.0rc1 by counting comment tokens towards the max_tokens limit.

Impact

This vulnerability allows unauthenticated attackers to cause denial of service through memory exhaustion by submitting GraphQL documents padded with many comments. The memory amplification can cause worker processes to exceed typical container memory limits (e.g., 256 MB or 512 MB), leading to out-of-memory kills. No data disclosure or modification occurs. Existing depth limiters and complexity analyzers do not mitigate this issue because they operate after parsing, which succeeds with only a few real tokens.

Summary

GraphQL-core's parser has a flaw where the max_tokens limit, intended to restrict oversized GraphQL documents, does not count comment tokens. The lexer skips comments when returning tokens but still allocates Token objects for each comment, linking them into a persistent token list retained for the document's lifetime. The parser only increments the token count for non-comment tokens, allowing documents padded with many comments to bypass the max_tokens check. This leads to significant memory amplification, as demonstrated by a 38 MB comment-padded payload causing approximately 92 MB of additional resident memory usage. The vulnerability enables denial of service via memory exhaustion without requiring authentication. The issue was fixed in GraphQL-core versions 3.2.12 and 3.3.0rc1 by modifying the parser to count all tokens, including comments, towards the max_tokens limit. Users may need to adjust max_tokens limits if they parse documents with many comments.

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Description

AI analysisMachine-generated, updated 30 Oct 2026, 05:44 UTC

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