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Debian LinuxOperating system · Debian

CVE-2018-0488

CRITICAL · 9.8 CVSS v3.0 Published 2018-02-13
Fix available
A fix is available. Upgrade to 1.3.22 / 2.1.10 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ARM mbed TLS before 1.3.22, before 2.1.10, and before 2.7.0, when the truncated HMAC extension and CBC are used, allows remote attackers to execute arbitrary code or cause a denial of service (heap corruption) via a crafted application packet within a TLS or DTLS session.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Heap corruption vulnerability in ARM mbed TLS allows remote code execution when the truncated HMAC extension is used together with CBC mode ciphers. Attackers send crafted application packets within TLS/DTLS sessions to trigger heap corruption, potentially achieving arbitrary code execution.

MitigationUpgrade mbed TLS to version 1.3.22, 2.1.10, or 2.7.0 or later. If immediate upgrade is not possible, disable the truncated HMAC extension or avoid using CBC mode ciphers.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 8.0= 9.0
Mbed TlsApplication
Affected:>= 1.3.0, < 1.3.22>= 2.1.0, < 2.1.10>= 2.2.0, < 2.7.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify mbed TLS installation and version
    Run `dpkg -l | grep mbedtls` on Debian systems, or check for library files like `libmbedtls.so`, `libmbedcrypto.so` using `ldconfig -p | grep mbed`. Examine the library or binary version with `strings` or `file`, or check application bundling.
    Affected if Installed version falls within 1.3.0 to 1.3.21, 2.1.0 to 2.1.9, or 2.2.0 to 2.6.0
  2. Locate mbed TLS configuration files
    Search for `mbedtls_config.h` or `config.h` in the application or system include paths. Common locations: `/usr/include/mbedtls/`, `/usr/local/include/mbedtls/`, or within the application's source tree.
    Affected if Configuration file exists and contains mbed TLS version in the vulnerable range
  3. Verify truncated HMAC extension is enabled
    Search the configuration file for `MBEDTLS_SSL_TRUNCATED_HMAC_ENABLED` or the macro `SSL_TRUNCATED_HMAC`. If building from source, check that this option is not commented out or set to 0.
    Affected if Truncated HMAC (SSL_TRUNCATED_HMAC) is defined and enabled in the configuration
  4. Confirm CBC mode ciphers are available
    Check the cipher suite configuration for presence of CBC-based suites such as TLS_RSA_WITH_AES_128_CBC_SHA, TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA, or similar CBC mode cipher suites. Look for `MBEDTLS_CIPHER_MODE_CBC` in the build config.
    Affected if CBC mode cipher suites are enabled in the TLS configuration
  5. Check active TLS/DTLS sessions
    Use network capture tools like `tcpdump` or `tshark` to inspect TLS/DTLS handshake and application data packets. Examine ClientHello for truncated HMAC extension presence (`0x00 0x03` extension type) and negotiated cipher suites.
    Affected if Active TLS/DTLS sessions are using both truncated HMAC extension and CBC mode cipher suites

The environment is affected if mbed TLS version is 1.3.0-1.3.21, 2.1.0-2.1.9, or 2.2.0-2.6.0, AND the truncated HMAC extension is enabled, AND CBC mode cipher suites are in use.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 1.3.22 / 2.1.10 / 2.7.0 or later
Fixed in 1.3.222.1.102.7.0
Interim mitigation

Upgrade mbed TLS to version 1.3.22, 2.1.10, or 2.7.0 or later. If immediate upgrade is not possible, disable the truncated HMAC extension or avoid using CBC mode ciphers.

Recommended fix High confidence

Upgrade to mbed TLS 1.3.22 (for 1.3.x branch), 2.1.10 (for 2.1.x branch), or 2.7.0 (for 2.2.x-2.6.x branch); Debian users should apply all available security updates

  1. Identify the installed mbed TLS version by checking library files (e.g., libmbedtls, libmbedcrypto) or the package manager
  2. For Debian systems: run 'apt-get update && apt-get install libmbedtls*' to obtain updated packages from Debian security repositories
  3. If using mbed TLS as a standalone library: download the fixed release corresponding to your branch (1.3.22, 2.1.10, or 2.7.0) from the official mbed TLS repository at github.com/ARMmbed/mbedtls
  4. Verify the integrity of downloaded packages using provided checksums or signatures
  5. Recompile any applications linked against the old mbed TLS library
  6. Restart any services using mbed TLS to ensure the new version is loaded
  7. Verify the fix by confirming the new version is active: 'openssl s_client -connect <host>:<port>' or checking library version at runtime
Caveat Minor: mbed TLS 2.x introduced some API changes from 1.3.x; verify application compatibility if upgrading across major branches

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,440
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2018-0488 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data