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CVE-2026-101050· NVD / CVE Program· CNA VulnCheck

Heym before 0.0.53 Authentication Bypass via Telegram Webhook

Heym before 0.0.53 fails to verify the X-Telegram-Bot-Api-Secret-Token header on Telegram webhook endpoints when credential_id is absent or secret_token is empty. Remote unauthenticated attackers can post forged Telegram updates to trigger workflows with the owner's configured credentials and execute actions on attacker-supplied input.

HighCVSS 8.3 · v4.0—No exploit Fix available
Published
Sep 27, 2026
Updated
Sep 28, 2026
EPSS
0.3% · 20th percentile
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Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
8.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • heymrun heym

    • 0.0.53not affected
    • before 0.0.53affected · semver

Same product

heymrun: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-100865Heym before 0.0.53 Remote Code Execution via eval() Sandbox Escape
    34Monitor
  • CVE-2026-100864heym before 0.0.91 Remote Code Execution via Expression Engine
    34Monitor
  • CVE-2026-45227Heym < 0.0.21 Sandbox Escape via Python Introspection
    34Monitor
  • CVE-2026-101049Heym before 0.0.53 Slack Webhook Signature Verification Bypass
    33Monitor
  • CVE-2026-100858heym before 0.0.109 Server-Side Request Forgery via Workflow Nodes
    30Monitor
  • CVE-2026-45226Heym < 0.0.21 Authorization Bypass in Workflow Execution
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
heymrun heym0.0.53Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-1010490 days apartHeym before 0.0.53 Slack Webhook Signature Verification Bypass
    33Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2026-1008650 days apartHeym before 0.0.53 Remote Code Execution via eval() Sandbox Escape
    34Monitor
  • CVE-2026-1008580 days apartheym before 0.0.109 Server-Side Request Forgery via Workflow Nodes
    30Monitor
  • CVE-2026-1008610 days apartheym before 0.0.105 SSRF via credential-controlled base URLs
    21Monitor
  • CVE-2026-1008630 days apartHeym before 0.0.91 SSRF via image fetching and IPv6 validation
    21Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);

Fixed

ts
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓
  2. SSVC exploitation— → poc

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records