Forge: Regular expression denial of service in PEM decoding (pem.decode) (CVE-2026-118779)
Published Last modified Sources: OSV, Hersteller, CVE.org
What is affected, what to do
Update Digitalbazaar Forge to version 1.4.1.
- Affected
- Digitalbazaar Forge
lt *..1.4.1
- Digitalbazaar Forge
- Fixed in
- Digitalbazaar Forge
1.4.1
- Digitalbazaar Forge
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Metrics
7.5
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: Vendor (CNA), CVSS v3
7.5
CVSS v3
Severity High on the scale from 0 to 10.
Source: OSV, Hersteller, CVE.org
0.6 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 46.4
Show all metrics
- Severity
- High
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 84.73 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 7.5 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 7.5
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.6 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 46.4
- High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
- CISA assessment (SSVC)
- Exploitation: proof of concept · automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 29 October 2026
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-1333, CWE-400
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- High technical severity: assess and remediate the vulnerability in vulnerability handling under Art. 21(2)(e) NIS2 and document the decision.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Summary
pem.decode(), which every node-forge API that parses PEM input uses, split messages with a regular expression that takes polynomial time on input without a matching END line, and parsed encapsulated headers with regular expressions that take quadratic time on long header lines. A remote attacker can block the Node.js event loop for seconds to minutes with a crafted input of a few tens of kilobytes. Fixed in node-forge 1.4.1.
Details
pem.decode() in lib/pem.js found PEM messages with this regular expression:
/\s*-----BEGIN ([A-Z0-9- ]+)-----\r?\n?([\x21-\x7e\s]+?(?:\r?\n\r?\n))?([:A-Za-z0-9+\/=\s]+?)-----END \1-----/g
The optional headers group and the body group are adjacent, lazy, and share characters (whitespace and the base64 alphabet), and the match must end with an END line whose label equals the BEGIN label (\1). When no such END line follows, the engine tries every split of the text between the two groups, for every label split and at every BEGIN line in the input. The work grows polynomially with the input length (roughly cubic for repeated BEGIN/END lines with mismatched labels, quadratic for a BEGIN line followed by many newlines).
The encapsulated header parsing in the same function had two smaller quadratic cases: trimming each header line with /\s+$/, and an unanchored header regex ([\x21-\x7e]+):... that retries at every position of a long line without a colon. These are reachable when a message does match.
All PEM entry points call pem.decode(), including pki.certificateFromPem(), pki.privateKeyFromPem(), pki.publicKeyFromPem(), pki.certificationRequestFromPem(), pki.encryptedPrivateKeyFromPem(), pki.decryptRsaPrivateKey() and pkcs7.messageFromPem().
The fix replaces the message regular expression with a scanner that indexes the END lines once and matches each BEGIN line in linear time, finding the same messages as before. The one difference: a label containing ----- (-----BEGIN A-----B-----) was matched as A-----B if possible; now only the shortest label, A, is used. RFC 7468 labels can't contain --. Header parsing now trims lines with a loop and only starts a header match at the beginning of a run of printable characters, which gives the same result.
Patches
Fixed in node-forge 1.4.1. PEM messages and encapsulated headers are now parsed in linear time.
Workarounds
Rejecting untrusted PEM input larger than a few kilobytes before passing it to node-forge limits the delay but doesn't remove it: on 1.4.0, about 7 KB of crafted input blocked for 0.4 s, and 29 KB for 24 s.
Credits
Reported by Ahmed Mokhtari (@AhmedMokhtari), @mwlik and @imenyoo2, and independently by @offset, @bibu123456 (coordinated by @Kayiz-PT), and @Mucahic.
Proof of concept
var forge = require('node-forge');
var pem = ' -----BEGIN I-----G-----END B'.repeat(1000) + '\x00'; // 29 KB
try {
forge.pki.certificateFromPem(pem);
} catch(e) {}
On 1.4.0 (Node.js 24) this call blocks for about 24 seconds before throwing "Invalid PEM formatted message."; 14 KB takes about 3 seconds. A BEGIN line followed by 32 KB of newlines and no END line takes about 1.5 seconds, and the time grows quadratically from there. On 1.4.1 each of these inputs is rejected in a few milliseconds, and 1 MB inputs of any of these shapes take under 100 ms.
The PoC is in tests/pocs/ghsa-7wch-p9px-956x.js. Regression tests are in tests/unit/pem.js ("GHSA-7wch-p9px-956x ReDoS checks").
Impact
Any application that passes untrusted PEM text to node-forge is affected: for example, services that accept uploaded certificates, keys or certificate signing requests, or that parse certificates from configuration, SAML metadata or other user-supplied documents. A remote, unauthenticated attacker can send a small crafted input that blocks the Node.js event loop for seconds to minutes per request, so the process stops serving other requests. Repeated requests keep it unavailable. There is no confidentiality or integrity impact.
Source: OSV (Open Source Vulnerabilities), GitHub Security Advisories, NVD (NIST), cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| digitalbazaar | forge |
|
|
| npm | node-forge |
|
|
Vendors and products
Weakness classes (CWE)
CWE-1333Inefficient Regular Expression Complexity
Base
The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.
Entry at MITRE CWE-1333CWE-400Uncontrolled Resource Consumption
Class
The product does not properly control the allocation and maintenance of a limited resource.
Entry at MITRE CWE-400
References & sources
- github.comdigitalbazaar/forge/commit/412345db583cd28a9d23636d0d93e9f751b9…x_refsource_MISC, web
- github.comdigitalbazaar/forge/releases/tag/v1.4.1x_refsource_MISC, web
- github.comdigitalbazaar/forge/security/advisories/GHSA-7wch-p9px-956xx_refsource_CONFIRM, web
- NVD (NIST)vuln/detail/CVE-2026-118779advisory
- github.comdigitalbazaar/forgepackage
Changes to this CVE
Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: proof of concept, automatable: yes
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://github.com/digitalbazaar/forge/security/advisories/GHSA-7wch-p9px-956xSSVC assessment added —{"id":"CVE-2026-118779","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"version":"2.0.3","timestamp":"2026-10-29T20:22:46.362205Z"}Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0
ReceivedGitHub
CVSS V3.1: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness type: CWE-400, CWE-1333
Description added or changed
Show 8 original changes
Individual changes of this event as published by NVD Type Action Before After Description added —Forge (also called node-forge) is a native implementation of Transport Layer Security in JavaScript. Prior to 1.4.1, the affected implementation used pem.decode(), lib/pem.js, missing END line to process the relevant input or security decision. node-forge used polynomial-time regular expressions in pem.decode(), including when searching for a matching END line and parsing encapsulated headers. An unauthenticated attacker able to supply PEM input to any high-level parser could consume excessive CPU with a long malformed message and cause denial of service. This issue is fixed in version 1.4.1.CVSS added —AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HWeakness type (CWE) added —CWE-400Weakness type (CWE) added —CWE-1333Affected versions (publisher) added —New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/118xxx/CVE-2026-118779.json">CVE-2026-118779</a>Reference added —https://github.com/digitalbazaar/forge/commit/412345db583cd28a9d23636d0d93e9f751b935f3Reference added —https://github.com/digitalbazaar/forge/releases/tag/v1.4.1Reference added —https://github.com/digitalbazaar/forge/security/advisories/GHSA-7wch-p9px-956xSource identifier: security-advisories@github.com
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<a href="https://intel.neosec.eu/en/cve/CVE-2026-118779"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-118779.svg?lang=en" alt="CVE-2026-118779 – NEOSEC Intel" height="20"></a>