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CVE-2026-68537 high CVSS 7.5

Vulnerability in fulgur (CVE-2026-68537)

Summary

Vulnerability in fulgur (CVE-2026-68537). Risk of unauthorized operations or information disclosure. Exploitable via fulgur. Mitigation: upgrade to 0.26.0 or later.

Original description

The description as published by the source.

fulgur converts untrusted HTML/CSS into PDF, commonly on a server that
processes input supplied by many tenants. In versions prior to 0.26.0, a
childless box that resolves to a pathologically tall height was amplified into
thousands of blank PDF pages, even when it produces no visible output.

The childless-collapse defense that would normally collapse such a box was gated
by a tag-only "replaced content" check, so any non-painting replaced element
bypassed it, including an unresolved src (the common offline-first case), a
visibility:hidden image, an undecodable image format, and an empty ``. A
trailing-sibling variant of the same gap was also open.

A few bytes of HTML therefore amplified into roughly MAX_PAGES (10,000) blank
pages; the renderer allocates and runs a per-page loop over them, producing CPU
and memory exhaustion. An attacker able to submit HTML to a fulgur-based
conversion service can trigger this with a trivially small payload, denying
service to the host and any co-tenants.

Fixed in 0.26.0: the tag-only gate was removed so that any pathologically tall
childless box collapses regardless of whether it is a replaced element, closing
the missing-src, visibility:hidden, undecodable-format, and empty-``
vectors along with the trailing-sibling variant.

Versions prior to 0.19.0 additionally lacked any page-count cap, allowing an
unbounded (rather than 10,000-page) variant of this amplification; that earlier
variant is tracked separately as GHSA-j5cx-ph8…

Source: NIST National Vulnerability Database NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-68537 has been found in fulgur.
Attackers can target a specific entry point like fulgur over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade fulgur to 0.26.0 or later.
If unsure, ask your IT team or search "fulgur CVE-2026-68537" on the vendor's site.

CVE-2026-68537 (fulgur) — CWE-400 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: fulgur / src / MAX_PAGES / height
Patched: 0.26.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-400) exists in fulgur. Attackers reach the vulnerable code path via fulgur without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of fulgur. Attack surface: fulgur / src / MAX_PAGES / height.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 0.26.0.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'fulgur' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r 'fulgur' . | grep -v node_modules

    リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で fulgur を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Apply patch patch 
    Upgrade fulgur to 0.26.0

    ステージング環境で 0.26.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。

  3. 3
    Post-deployment verification verify 
    Confirm patched version is live in production

    パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

rust fulgur
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.26.0"}]}]
crates.io fulgur
[{"type":"SEMVER","events":[{"introduced":"0.0.0-0"},{"fixed":"0.26.0"}]}]

References

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