# CVE-2026-119036: Business::GoCardless versions before 1.01 for Perl allow memory exhaustion by flattening legacy webhook payloads before checking their signature

Status: published. Published: 2026-10-30. Updated: 2026-11-06.

Business::GoCardless versions before 1.01 for Perl allow memory exhaustion by flattening legacy webhook payloads before checking their signature.

A webhook body with a top-level "payload" key is verified as a legacy webhook. To rebuild the signed string, the payload is flattened into one key and value pair per leaf, each key carrying the full path to that leaf, and the pairs are then encoded, sorted and joined. A long key holding a long array costs memory proportional to the key length times the array length.

A remote attacker can exhaust memory in the process receiving webhooks with a single request that carries no valid signature.

## Remediation

- fix: Upgrade to Business-GoCardless 1.01 or later. (source: CNA: CPANSec)

## Affected products and versions

-  /  (Business-GoCardless): ≥ 0; < 1.01 (affected, custom). Source: CNA: CPANSec

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: ADP: CISA-ADP

- CISA KEV: No listing in collected sources

- EPSS: 0.18% as of 2026-11-06; percentile 7.12%

- SSVC: exploitation none; automatable yes; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://metacpan.org/release/LEEJO/Business-GoCardless-1.01/changes (CNA: CPANSec; release-notes)

## Provenance

- CNA: CPANSec: https://www.cve.org/CVERecord?id=CVE-2026-119036; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-119036; retrieved 2026-11-06; source updated Not reported

Revision: 4d1d2555268abae7aad2f26665e95495e45ada980298ec7713c453fc90a0f924

Canonical: https://y2.dev/cve/CVE-2026-119036

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