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Quill is a tool for signing and notarizing macOS binaries from any platform . During the Apple notarization process, it makes HTTP requests to Apple’s API. In versions before v0.7.1, Quill contains a vulnerability where it reads the entire HTTP response body into memory without any size limits . Exploitation requires the ability to modify API responses from Apple’s notarization service. This is not possible under standard network conditions due to HTTPS with proper TLS certificate validation. However, environments with TLS-intercepting proxies, compromised certificate authorities, or other trust boundary violations are at risk. An attacker who can control or modify the response content can return an arbitrarily large payload. This causes the Quill client to run out of memory and crash . The vulnerability is a classic case of missing bounds checking on network input. It affects both the Quill CLI and library when used for notarization operations. The impact is limited to availability, with no effect on confidentiality or integrity. The issue has been fixed in Quill version v0.7.1 . No workarounds are available; users must upgrade to the patched version. The vulnerability was reported by opera-aklajn (Opera) and credited by Anchore.
Platform: Quill
Version: v0.7.1
Vulnerability: Unbounded HTTP read
Severity: Medium (CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H, Score 5.3)
date: March 11, 2026
Prediction: Patch already available (v0.7.1)
What Undercode Say:
Analytics:
Check installed Quill version
quill version
Determine if your version is vulnerable (versions < v0.7.1)
vulnerable_version_check() {
current_version=$(quill version 2>&1 | grep -oE 'v[0-9]+.[0-9]+.[0-9]+')
if [[ -z "$current_version" ]]; then
echo "Quill not found or version could not be determined."
elif [[ "$current_version" < "v0.7.1" ]] && [[ "$current_version" != v ]]; then
echo "Vulnerable version detected: $current_version. Upgrade to v0.7.1 or later."
elif [[ "$current_version" < "v0.7.1" ]]; then
echo "Vulnerable version detected: $current_version. Upgrade to v0.7.1 or later."
else
echo "Quill version $current_version is not vulnerable to CVE-2026-31960."
fi
}
vulnerable_version_check
// Hypothetical vulnerable code pattern in Go (illustrative)
package main
import (
"io"
"net/http"
)
func notarizeHandler(w http.ResponseWriter, r http.Request) {
// ... request to Apple Notary API ...
resp, err := http.Get("https://api.apple.com/notarization")
if err != nil {
// handle error
}
defer resp.Body.Close()
// VULNERABILITY: No limit on reading response body
body, _ := io.ReadAll(resp.Body) // Reads unbounded data into memory
// ... process body ...
_ = body // Use body
}
Exploit:
This is a conceptual representation of the attack, not executable code. An attacker controlling a TLS-intercepting proxy would: 1. Wait for a Quill notarization request. 2. Forward the request to the real Apple server. 3. Intercept the response from Apple and replace it with a malicious payload. The malicious response would contain an extremely large body, e.g., a single HTTP response with gigabytes of data. Example of a malicious HTTP response header: HTTP/1.1 200 OK Content-Type: application/json Content-Length: 9999999999 [Gigabytes of arbitrary data, e.g., 'A' repeated infinitely]
Protection from this CVE:
Upgrade to the patched version curl -sSfL https://raw.githubusercontent.com/anchore/quill/main/install.sh | sh -s -- -b /usr/local/bin v0.7.1 Alternatively, download the latest release from GitHub https://github.com/anchore/quill/releases Verify the installation quill version Expected output: v0.7.1 or higher In CI/CD environments, ensure that TLS interception proxies are configured securely and that network boundaries are properly trusted. For code review: ensure that all HTTP response bodies are read with a limit, for example using `http.MaxBytesReader` in Go.
Impact:
The primary impact is a Denial of Service (DoS). Successful exploitation causes the Quill process to crash due to memory exhaustion. This disrupts software build and release pipelines that depend on notarization. The crash affects availability only; no code execution or data theft is possible. CI/CD systems using TLS-intercepting proxies are most at risk.
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Sources:
Reported By: github.com
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