Merge #1178: Reduce the prominence of examples in the security advisories page

0e8f0c8 pages: use bullet points for severity levels on security advisories page (Antoine Poinsot)
cbb872a pages: encapsulate examples in collapsible section on advisory page (Antoine Poinsot)

Pull request description:

  In #1147 we added examples for each severity level. While this is useful to have as an illustration in the policy, this made the first part of the "Policy" section take a lot more space. It takes almost 1.5x the height of my high resolution office monitor. This means scrolling up more than one entire page before getting to the disclosure timeline, let alone the latest publish advisories.

  This PR reduces the prominence of the severity level by reducing the size of the section titles and by putting the example under a collapsible section.

  Here is how it changes the display for me.

  Before:
  <img width="2004" height="1319" alt="image" src="https://github.com/user-attachments/assets/96bbae32-4b5c-4a55-8386-3814c97b0512" />

  After:
  <img width="2004" height="1319" alt="image" src="https://github.com/user-attachments/assets/af84efcb-86d0-448b-b172-ed7522df821a" />

ACKs for top commit:
  achow101:
    ACK 0e8f0c8
  janb84:
    ACK 0e8f0c8

Tree-SHA512: eb8d92f6bc9743797b00a5481e4c1299434681493d195822d5bd36be7731cd683735e139bb85336d8a715eb65e1b37ec03df5d4a30ef240bf084feffb216f28b

Author: achow101

_posts/en/pages/2024-06-26-security-advisories.md

@@ -19,75 +19,85 @@ All vulnerabilities should be reported to security@bitcoincore.org (see
 [SECURITY.md](https://github.com/bitcoin/bitcoin/blob/master/SECURITY.md) for
 details). When reported, a vulnerability will be assigned a severity category.
 We differentiate between 4 classes of vulnerabilities:
-
-### Critical
-
-Bugs that threaten the fundamental security and integrity of the entire Bitcoin
-network. These are bugs that allow for coin theft at the protocol level, the
-creation of coins outside of the specified issuance schedule, or permanent,
-network-wide chain splits.
-
-Examples:
-* A bug allowing inflating the money supply by spending the same transaction
-  output twice within a block ([CVE-2018-17144](/en/2018/09/20/notice/)).
-* A consensus failure where nodes running older software rejected a block that
-  newer software accepted due to an underlying database limit, causing a
-  network-wide chain split ([BIP
-  50](https://github.com/bitcoin/bips/blob/master/bip-0050.mediawiki)).
-
-### High
-
-Bugs with a significant impact on affected nodes or the network. These are
-typically exploitable remotely under default configurations and can cause
-widespread disruption.
-
-Examples:
-* A remotely triggerable crash that could take many nodes offline
-  ([CVE-2024-35202](/en/2024/10/08/disclose-blocktxn-crash/)).
-* A denial-of-service attack that causes a node to stall for an extended
-  period, preventing it from processing new transactions and blocks
-  ([CVE-2024-52914](/en/2024/07/03/disclose-orphan-dos/)).
-* A memory exhaustion vulnerability that could be triggered remotely to crash
-  nodes by having them store an excessive amount of block headers
-  ([CVE-2019-25220](/en/2024/09/18/disclose-headers-oom/)).
-
-### Medium
-
-Bugs that can noticeably degrade the network's or a node's performance or
-functionality, but are limited in their scope or exploitability. These might
-require special conditions to trigger, such as non-default settings, or result
-in service degradation rather than a complete node failure.
-
-Examples:
-* A potential Remote Code Execution (RCE) vulnerability on the local network
-  that is only exploitable if a non-default feature like UPnP is enabled
-  ([CVE-2015-20111](/en/2024/07/03/disclose_upnp_rce/)).
-* A peer could hinder block propagation by sending mutated blocks, delaying the
-  reception of new blocks for a node
-  ([CVE-2024-52921](/en/2024/10/08/disclose-mutated-blocks-hindering-propagation/)).
-* An attacker announcing a block to a node and then failing to provide it,
-  causing the victim node to wait for up to 10 minutes before being able to
-  fetch it from another peer
-  ([CVE-2024-52922](/en/2024/11/05/cb-stall-hindering-propagation/)).
-
-### Low
-
-Bugs that are challenging to exploit or have a minor impact on a node's
-operation. They might only be triggerable under non-default configurations or
-from the local network, and do not pose an immediate or widespread threat.
-
-Examples:
-* A malformed `getdata` message could cause a peer connection to enter an
-  infinite loop, consuming CPU but not affecting the node's ability to process
-  blocks or handle other peer connections
-  ([CVE-2024-52920](/en/2024/07/03/disclose-getdata-cpu/)).
-* A bug in a dependency that could crash a node, but only if a non-default
-  feature like UPnP is enabled
-  ([CVE-2024-52917](/en/2024/07/31/disclose-upnp-oom/)).
-* A bug that could crash a node, but is extremely difficult to exploit
-  ([CVE-2024-52919](/en/2025/04/28/disclose-cve-2024-52919/)).
-
----
+* **Critical**: Bugs that threaten the fundamental security and integrity of the entire Bitcoin
+  network. These are bugs that allow for coin theft at the protocol level, the
+  creation of coins outside of the specified issuance schedule, or permanent,
+  network-wide chain splits.
+  <details markdown="1">
+
+  <summary>
+  Examples
+  </summary>
+
+  * A bug allowing inflating the money supply by spending the same transaction
+    output twice within a block ([CVE-2018-17144](/en/2018/09/20/notice/)).
+  * A consensus failure where nodes running older software rejected a block that
+    newer software accepted due to an underlying database limit, causing a
+    network-wide chain split ([BIP
+    50](https://github.com/bitcoin/bips/blob/master/bip-0050.mediawiki)).
+
+  </details>
+* **High**: Bugs with a significant impact on affected nodes or the network. These are
+  typically exploitable remotely under default configurations and can cause
+  widespread disruption.
+  <details markdown="1">
+
+  <summary>
+  Examples
+  </summary>
+
+  * A remotely triggerable crash that could take many nodes offline
+    ([CVE-2024-35202](/en/2024/10/08/disclose-blocktxn-crash/)).
+  * A denial-of-service attack that causes a node to stall for an extended
+    period, preventing it from processing new transactions and blocks
+    ([CVE-2024-52914](/en/2024/07/03/disclose-orphan-dos/)).
+  * A memory exhaustion vulnerability that could be triggered remotely to crash
+    nodes by having them store an excessive amount of block headers
+    ([CVE-2019-25220](/en/2024/09/18/disclose-headers-oom/)).
+
+  </details>
+* **Medium**: Bugs that can noticeably degrade the network's or a node's performance or
+  functionality, but are limited in their scope or exploitability. These might
+  require special conditions to trigger, such as non-default settings, or result
+  in service degradation rather than a complete node failure.
+  <details markdown="1">
+
+  <summary>
+  Examples
+  </summary>
+
+  * A potential Remote Code Execution (RCE) vulnerability on the local network
+    that is only exploitable if a non-default feature like UPnP is enabled
+    ([CVE-2015-20111](/en/2024/07/03/disclose_upnp_rce/)).
+  * A peer could hinder block propagation by sending mutated blocks, delaying the
+    reception of new blocks for a node
+    ([CVE-2024-52921](/en/2024/10/08/disclose-mutated-blocks-hindering-propagation/)).
+  * An attacker announcing a block to a node and then failing to provide it,
+    causing the victim node to wait for up to 10 minutes before being able to
+    fetch it from another peer
+    ([CVE-2024-52922](/en/2024/11/05/cb-stall-hindering-propagation/)).
+
+  </details>
+* **Low**: Bugs that are challenging to exploit or have a minor impact on a node's
+  operation. They might only be triggerable under non-default configurations or
+  from the local network, and do not pose an immediate or widespread threat.
+  <details markdown="1">
+
+  <summary>
+  Examples
+  </summary>
+
+  * A malformed `getdata` message could cause a peer connection to enter an
+    infinite loop, consuming CPU but not affecting the node's ability to process
+    blocks or handle other peer connections
+    ([CVE-2024-52920](/en/2024/07/03/disclose-getdata-cpu/)).
+  * A bug in a dependency that could crash a node, but only if a non-default
+    feature like UPnP is enabled
+    ([CVE-2024-52917](/en/2024/07/31/disclose-upnp-oom/)).
+  * A bug that could crash a node, but is extremely difficult to exploit
+    ([CVE-2024-52919](/en/2025/04/28/disclose-cve-2024-52919/)).
+
+  </details>
 
 **Low** severity vulnerabilities will be disclosed 2 weeks after the release of a major version
 containing the fix. **Medium** and **High** severity vulnerabilities will be disclosed 2 weeks after