How severe is CVE-2026-106558?

CVE-2026-106558 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-106558 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-106558?

CVE-2026-106558 primarily affects Linuxfoundation Backstage Plugin-techdocs-node. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-106558?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-106558 published?

CVE-2026-106558 was published on 2026-10-07 and last updated on 2026-10-13.

CVE-2026-106558

CVE-2026-106558 is a high-severity vulnerability in Linuxfoundation Backstage Plugin-techdocs-node with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 0% (40th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-502
Affected product: Linuxfoundation Backstage Plugin-techdocs-node
Published: 2026-10-07
Last modified: 2026-10-13

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.

Frequently asked questions

What is CVE-2026-106558?: 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.
How severe is CVE-2026-106558?: CVE-2026-106558 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-106558 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-106558?: CVE-2026-106558 primarily affects Linuxfoundation Backstage Plugin-techdocs-node. In total, 11 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-106558?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-106558 published?: CVE-2026-106558 was published on 2026-10-07 and last updated on 2026-10-13.

References

Affected products (11)

cpe:2.3:a:linuxfoundation:backstage_plugin-techdocs-node:*:*:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:*:*:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.51.0:-:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.51.0:next0:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.51.0:next1:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.51.0:next2:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.51.0:next3:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.55.0:-:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.55.0:next0:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.55.0:next1:*:*:*:*:*:*
cpe:2.3:a:linuxfoundation:backstage:1.55.0:next2:*:*:*:*:*:*

More vulnerabilities in Linuxfoundation Backstage Plugin-techdocs-node

CVE-2026-88064 — High (CVSS 8.8): Backstage is an open framework for building developer portals. Prior to 1.14.6 and from 1.15.0 until 1.15.4, the…
CVE-2026-106556 — High (CVSS 7.7): Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node…
CVE-2026-106510 — High (CVSS 7.7): Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node…
CVE-2026-106509 — High (CVSS 7.7): Backstage is an open framework for building developer portals. Prior to 1.14.6, the @backstage/plugin-techdocs-node…
CVE-2026-106505 — High (CVSS 7.7): Backstage is an open framework for building developer portals. Prior to 1.14.6 and 1.15.4, the…
CVE-2026-106455 — High (CVSS 7.7): Backstage is an open framework for building developer portals. From 0.11.12 until 1.14.7 and 1.15.5, the…

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