8.8

CVE-2026-106558: backstage Deserialization of Untrusted Data

CVSS: 8.8v3.1HighAnalyzed
AliasesGHSA-qmw3-745m-w99g
Published 07-10-2026Last modified 10-10-2026
Open JSON

Vulnerability summary

CVE-2026-106558 is a high (CVSS 8.8) Deserialization of Untrusted Data vulnerability in backstage. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.2% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v3.1 (CVE.org)
EPSS score
0.47%
0%100%
Low · Change unavailable
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 07-10-2026
    PublishedVulnerability first disclosed.
  2. 10-10-2026
    Last modifiedVulnerability information updated.

Description

Backstage is an open framework for building developer portals. Prior to 1.14.8, 1.15.6, and 2.0.1, the @backstage/plugin-techdocs-node package improperly validated mapping-style markdown_extensions configuration. An authenticated attacker who can register or influence an SCM-backed documentation source may bypass TechDocs sanitization and cause Python objects to be imported and instantiated in the generator runtime, leading to arbitrary code execution. Earlier fixes in versions 1.14.6 and 1.15.4 did not fully address the supported mapping representation of markdown_extensions. Impact is greatest when documentation generation runs with backend credentials, filesystem access, or internal network access. This issue is fixed in versions 1.14.8, 1.15.6, and 2.0.1.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.47%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

08-10-202619-10-2026
EPSS score
0.47%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

@backstage2 products
  • plugin-techdocs-node< 1.14.8 | ≥ 1.15.0, < 1.15.6 | ≥ 2.0.0, < 2.0.1
  • plugin-techdocs-node< 1.15.4
Linuxfoundation2 products
  • backstage< 1.50.7 | ≥ 1.51.1, < 1.54.8 | ≥ 1.55.1, < 1.55.2 | 1.51.0 | 1.51.0:next0 | 1.51.0:next1 | 1.51.0:next2 | 1.51.0:next3 | 1.55.0 | 1.55.0:next0 | 1.55.0:next1 | 1.55.0:next2
  • backstage_plugin-techdocs-node< 1.14.8 | ≥ 1.15.0, < 1.15.6 | ≥ 2.0.0, < 2.0.1
Backstage1 product
  • backstage< 1.50.7 | ≥ 1.51.0-next.0, < 1.54.9 | ≥ 1.55.0-next.0, < 1.55.2

3 vendors · 5 products

References

9 links