CVE-2026-59877

protobufjs: Denial of Service via infinite loop in .proto option parsing

HIGH
7.5
CVSS Score
Published: July 8, 2026 at 03:28 PM UTC
Updated: October 25, 2026 at 05:10 PM UTC
1 product affected across 1 vendorProtobufjs

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Severity
HIGH7.5
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.6.5 and 8.6.6, protobufjs parsed option names by advancing through schema tokens until reaching an = token without checking for end of input, so a crafted .proto schema that opens an option declaration and ends prematurely can cause parse, Root.load, or Root.loadSync to loop indefinitely. This issue is fixed in versions 7.6.5 and 8.6.6.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 7.6.58.0.0 ≤ v < 8.6.6
Affected range stops below 7.6.5, so it looks safe — our inference, not a vendor statement
Affected range stops below 8.6.6, so it looks safe — our inference, not a vendor statement

References (6)

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-835

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