VulnerabilityPublished 10 Nov 2026

CVE-2026-125332: Forge · TLS client crash on an unsupported ServerHello compression method

Affects node-forgeSource GCVE Database

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Authoritative record:CVE-2026-125332· Medium 5.9

Not known to be exploited · CVSS 5.9 Medium : upgrade to 1.4.3 when convenient.

Data as of 10 Nov 2026, 22:34 UTC

CVSS 3.1 base score

5.9Medium

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	5.9

Patch: Available – fixed in 1.4.3

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

Attack Vector: Network
Attack Complexity: High
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: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
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 10 Nov 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 10 Nov 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 node-forge to 1.4.3.

Affected software

Product	Affected	Fixed in
npmnode-forge	Affected <1.4.3	Fixed in 1.4.3

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Description

### Summary A `forge.tls` client accepts any compression method in the ServerHello, although it only offers no compression. An unknown method makes `connection.process()` throw an uncaught `Error` when the client handles ServerHelloDone, before the server is authenticated. A malicious server or an on-path attacker can use this to terminate a Node.js process. Fixed in node-forge 1.4.3. ### Details The client's ClientHello offers only the `null` compression method. `tls.parseHelloMessage()` in `lib/tls.js` stores the ServerHello's `compression_method` for the client without checking it (the code has a `TODO: handle compression methods`). When the client handles ServerHelloDone it calls `tls.createConnectionState()`, which throws `Error('Unsupported compression algorithm.')` for any method other than `null` (0) and `deflate` (1). The exception propagates out of `connection.process()`. The ServerHello isn't authenticated until the server's Finished message, so an on-path attacker can change the compression byte of a genuine ServerHello; the certificate chain still verifies. Applications that pass socket data to `process()` without catching exceptions terminate. This includes `forge.tls.wrapSocket`, which calls `process()` from its socket data handler, and `forge.http`, which uses it. A `deflate` (1) method, also never offered, makes the handshake fail later with an error instead of a crash. Servers are not affected: a server always selects no compression. The fix fails the handshake with an `illegal_parameter` alert, through the connection's `error` callback, when the ServerHello selects any compression method other than `null`. #### Patches Fixed in node-forge 1.4.3. #### Workarounds Catch exceptions thrown by `connection.process()` and close the socket. #### Resources - RFC 5246, section 7.4.1.3 (Server Hello): https://www.rfc-editor.org/rfc/rfc5246#section-7.4.1.3 - Related: GHSA-525v-9gp9-w22h (another TLS client crash during the handshake, fixed in 1.4.1): https://github.com/digitalbazaar/forge/security/advisories/GHSA-525v-9gp9-w22h #### Severity CVSS 3.1: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H (5.9, Moderate) CVSS 4.0 (informational): CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N (8.2) CVSS 4.0 has no counterpart to 3.1's AC:H beyond AT:P and scores this higher; the severity rating follows CVSS 3.1. #### Credits Reported by @alienkeric. ### Proof of concept A server (or on-path attacker) sends a ServerHello with `compression_method` 0xff, followed by a valid Certificate and ServerHelloDone: client.handshake(); client.process(serverHello + certificate + serverHelloDone); // <= 1.4.2: throws Error: Unsupported compression algorithm. // 1.4.3: error callback with "Unsupported compression method." The reporter's PoC (a CA-issued server certificate and the default verify callback) is in tests/pocs/ghsa-w4xr-hqv8-ch44.js, and regression tests are in tests/unit/tls.js. ### Impact Applications that use `forge.tls` as a client (directly, through `forge.tls.wrapSocket`, or through `forge.http`) and pass data from a network socket to `connection.process()` are affected. The server they connect to, or an on-path attacker, can make `process()` throw before the server is authenticated; if the application doesn't catch it, the Node.js process terminates, dropping all its connections. Servers built on `forge.tls` are not affected. There is no confidentiality or integrity impact.

CWE-20Improper Input Validation (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #18OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design · Attack Surface Reduction
Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build "recognizers" for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of…
Architecture and Design · Libraries or Frameworks
Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
Architecture and Design · Implementation · Attack Surface Reduction
Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any…
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
Injection Prevention (opens in a new tab)
SQL Injection Prevention (opens in a new tab)
Injection Prevention in Java (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Server Side Include (SSI) Injection (opens in a new tab)
Cross Zone Scripting (opens in a new tab)
Command Line Execution through SQL Injection (opens in a new tab)
Object Relational Mapping Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-248Uncaught Exception (opens in a new tab)
Base weaknessOWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
An exception is thrown from a function, but it is not caught.
Requirements
The choice between a language which has named or unnamed exceptions needs to be done. While unnamed exceptions exacerbate the chance of not properly dealing with an exception, named exceptions suffer from the up call version of the weak base class problem.
Requirements
A language can be used which requires, at compile time, to catch all serious exceptions. However, one must make sure to use the most current version of the API as new exceptions could be added.
Implementation
Catch all relevant exceptions. This is the recommended solution. Ensure that all exceptions are handled in such a way that you can be sure of the state of your system at any given moment.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-20, CWE-248

Technical details

References

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