When running Debian's stable or stable-slim Docker images, users encounter a critical package management error when attempting updates:

E: The repository 'http://security.debian.org/debian-security stable/updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely

The root cause stems from how Debian handles repository naming conventions. The stable tag in Docker actually points to the codename-based release (e.g., Bookworm), but the security repository expects the codename rather than "stable" in its path.

For temporary operations, you can force APT to accept the insecure repository:

apt update --allow-insecure-repositories
apt upgrade --allow-unauthenticated

However, this is not recommended for production environments due to security implications.

Option 1: Use Release Codename

Modify your sources.list to use the actual release codename:

sed -i 's/stable/$(lsb_release -cs)/g' /etc/apt/sources.list
apt update

Option 2: Dockerfile Best Practice

For container builds, always pin to specific Debian versions:

FROM debian:bookworm-slim

RUN apt-get update && \
    apt-get install -y your-packages

To verify your current Debian version:

cat /etc/os-release
lsb_release -a

Check repository configuration:

apt-cache policy
cat /etc/apt/sources.list

• Avoid using floating tags like 'stable' in production containers
• Regularly rebuild containers when base images update
• Consider using Debian's snapshot repository for reproducible builds

For optimized production containers:

# Builder stage
FROM debian:bookworm-slim as builder
RUN apt-get update && \
    apt-get install -y build-essential && \
    make install

# Runtime stage
FROM debian:bookworm-slim
COPY --from=builder /usr/local/bin/ /usr/local/bin/
RUN apt-get update && \
    apt-get install -y runtime-dependencies

When running apt update in official Debian Docker containers (particularly debian:stable and debian:stable-slim), you might encounter this repository error:

E: The repository 'http://security.debian.org/debian-security stable/updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely

The root cause stems from how Debian manages its release channels. The stable tag in Docker actually points to Debian's testing branch, while the security repository expects a codename (like bookworm) rather than the stable label.

Here are three approaches to resolve this:

# Method 1: Use explicit codename
FROM debian:bookworm-slim

# Method 2: Disable security repo temporarily
RUN sed -i '/security.debian.org/d' /etc/apt/sources.list

# Method 3: Manual sources.list configuration
RUN echo "deb http://deb.debian.org/debian bookworm main" > /etc/apt/sources.list \
 && echo "deb http://security.debian.org/debian-security bookworm-security main" >> /etc/apt/sources.list

For Dockerfiles requiring security updates, always use explicit release names:

FROM debian:bookworm-slim

# Configure proper sources
RUN echo "deb http://deb.debian.org/debian bookworm main contrib non-free" > /etc/apt/sources.list \
 && echo "deb http://security.debian.org/debian-security bookworm-security main contrib non-free" >> /etc/apt/sources.list \
 && echo "deb http://deb.debian.org/debian bookworm-updates main contrib non-free" >> /etc/apt/sources.list

# Example package installation
RUN apt-get update && apt-get install -y \
    ca-certificates \
    curl \
    && rm -rf /var/lib/apt/lists/*

After making changes, verify with:

docker build -t debian-test .
docker run -it --rm debian-test apt update

If you're building images in CI pipelines, consider this pattern:

# Get current stable codename
DEB_RELEASE=$(curl -s http://deb.debian.org/debian/dists/ | grep -Po 'href="\K[^"]+' | grep -E '^[a-z]+$' | sort -r | head -1)

# Use in Dockerfile
sed -i "s/{{DEB_RELEASE}}/$DEB_RELEASE/g" Dockerfile

This automatically detects the current stable release codename.