Low · CVSS 2.1CVE-2026-81638

Non-canonical ULID spellings are accepted and alias to the same record in ash_double_entryCVE-2026-81638

Answer in brief

CVE-2026-81638 records a Low severity (CVSS 2.1) vulnerability in Non-canonical ULID spellings are accepted and alias to the same record in ash_double_entry. The current sources do not mark it as known exploited. The current feed maps ash-project/ash_double_entry (generic), ash-project/ash_double_entry (generic), ash-project/ash-project/ash_double_entry (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 7, 2026Updated Sep 8, 2026Source checked Oct 23, 2026First seen by HOL Sep 7, 2026Material review Sep 8, 2026

Upstream Advisory

Key facts

Risk: Low · CVSS 2.1
Exploitation: Not marked as known exploited
Affected software: 3 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 2.1. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps ash-project/ash_double_entry (generic), ash-project/ash_double_entry (generic), ash-project/ash-project/ash_double_entry (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
ash-project/ash_double_entrygeneric	>=1e5f7ce8ff25f519c904731a29eb1258324e561a <d3e688d300a581ae214b3ca7d95ef4de63fbb050	d3e688d300a581ae214b3ca7d95ef4de63fbb050
ash-project/ash_double_entrygeneric	>=0.1.0 <1.0.19	1.0.19
ash-project/ash-project/ash_double_entrygeneric	>=1e5f7ce8ff25f519c904731a29eb1258324e561a <d3e688d300a581ae214b3ca7d95ef4de63fbb050	d3e688d300a581ae214b3ca7d95ef4de63fbb050

Recommended response

Check inventory. Check lockfiles and deployed manifests for ash-project/ash_double_entry, ash-project/ash_double_entry, ash-project/ash-project/ash_double_entry.
Review the reported fix. Update ash-project/ash_double_entry to d3e688d300a581ae214b3ca7d95ef4de63fbb050; ash-project/ash_double_entry to 1.0.19; ash-project/ash-project/ash_double_entry to d3e688d300a581ae214b3ca7d95ef4de63fbb050 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 7, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 8, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 7, 2026

Sources and claim methodology

Upstream source description

Improper Handling of Alternate Encoding vulnerability in ash-project ash_double_entry allows an attacker to submit several distinct string spellings of the same identifier. AshDoubleEntry.ULID renders a 128-bit ULID as 26 Crockford base-32 characters, but the first character encodes only 3 bits, so canonical values are 0 to 7. decode/1 in lib/ulid.ex masks the first character to its low 3 bits and valid?/1 accepts all 32 characters in that position, so 0..., 8..., G... and R... decode to the identical 16-byte value and resolve to the same row. When the type is exposed as a public ID over an HTTP or API boundary, an attacker-supplied ID can be spelled differently from the record it actually reads or writes, desynchronizing or bypassing string-level checks such as idempotency and deduplication keys, deny-lists, audit correlation, or signatures computed over the submitted ID. This issue affects ash_double_entry: from 0.1.0 before 1.0.19.

Quoted source text, attributed separately from HOL analysis.