NVD / CVE Program· CNA EEF

CVE-2026-115693: Custom cacerts or cacertfile do not restrict trust to the pinned CA in hackney

Noroxi assessment

Priority: Monitor (action score 36/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.26% (FIRST EPSS).
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.
Fixed version: benoitc hackney 4.9.0, 915eb5737e9c489d8fc22eec8cdae30e9b027be4.

Low priority for now. Upgrade to benoitc hackney 4.9.0, 915eb5737e9c489d8fc22eec8cdae30e9b027be4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Improper Certificate Validation vulnerability in hackney_ssl in benoitc hackney allows an on-path attacker to impersonate a server pinned to a private certificate authority via a certificate chain that ends in a publicly trusted root. hackney adds {partial_chain, fun hackney_ssl:partial_chain/1} to every verify_peer configuration. The callback returns any certificate in the peer chain whose public key matches a root in the bundled certifi store as the trust anchor, and OTP honours that callback over the configured cacerts. hackney_ssl:merge_ssl_opts/3 kept the callback when the caller replaced the trust store with cacerts or cacertfile in ssl_options, so a connection pinned to a private CA still accepted any chain that carried a publicly trusted root. The hostname check still applies, so the attacker needs a publicly trusted certificate for the pinned hostname. This issue affects hackney: from 1.24.0 before 4.9.0.

CriticalCVSS 9.1 · v4.0—No exploit Fix available

EUVD-2026-109836

Published: Oct 26, 2026
Updated: Nov 2, 2026
EPSS: 0.2% · 18th percentile
CWE: CWE-295

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 36 / 40 · 9.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · EEF: 9.1; 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:H/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.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Running WordPress? Scan your site free with WP Lens

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

We use this product, ask for help

Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Check your site's encryption

This vulnerability is about certificate validation or weak cryptography. The free SSL checker tests your certificate, enabled TLS versions and weak ciphers.

Run the SSL check

Versions reported by the vendor

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

benoitc hackney
- 1.24.0 and later · before 4.9.0affected · semver
- d8a9afcf5c3849904274e2eba1df56c63d1a1a0c and later · before 915eb5737e9c489d8fc22eec8cdae30e9b027be4affected · git

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Hex	hackney	from 1.24.0 · before 4.9.0	4.9.0

Same product

benoitc: all records

Other highest-scoring records for the same primary product.

CVE-2026-47073Unbounded memory consumption in WebSocket client in hackney
34Monitor
CVE-2026-47067Atom table exhaustion via unrecognized URL schemes in hackney
34Monitor
CVE-2026-47066Infinite loop in Alt-Svc header parser in hackney
34Monitor

Published before and after this one in the same product

← EarlierCVE-2026-112880Oct 26, 2026 · CRLF injection in Proxy-Authorization header built from proxy_auth_fun in hackney
8Monitor
← EarlierCVE-2026-113440Oct 26, 2026 · HTTP/1.1 and HTTP/2 redirects resend basic_auth and cookie to a different scheme or port in hackney
24Monitor
Later →CVE-2026-115700Oct 26, 2026 · SSRF allowlist bypass via percent-encoded bracketed IPv6 or trailing-dot IP literal in hackney
27Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
benoitc hackney	4.9.0	Vendor (CNA)
benoitc hackney	915eb5737e9c489d8fc22eec8cdae30e9b027be4	Vendor (CNA)
Hex:hackney	4.9.0	Package registry (OSV)

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.

PublishedOct 26, 2026
Fix recordedOct 26, 2026same day
TodayNov 9, 2026+14 d

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.

Martin Karrerfinder
Jonatan Männchen / EEFcoordinator

Variant candidates

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

No nightly-computed relations.

Chain candidates

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

—

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-295 · Improper Certificate Validation

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/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

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

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

Vulnerable

kotlin

1override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {
2  // Left empty for the test environment
3}

Fixed

kotlin

1val client = OkHttpClient.Builder()
2  .certificatePinner(
3    CertificatePinner.Builder()
4      .add("api.sirius.example", "sha256/…")
5      .build()
6  ).build()

Attack context

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

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

SSVC exploitation— → noneNov 2, 2026, 9:07 PM UTC
Exploit maturity— → noneOct 26, 2026, 3:07 PM UTC
Fix✗ → ✓Oct 26, 2026, 3:07 PM UTC

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

References

cna.erlef.org/cves/CVE-2026-115693.html

Show all references (5 more)

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

All records