Cisco BroadWorks: security flaw used in attacks
OFFICIAL NAME: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability
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TECHNICAL SUMMARY Cisco BroadWorks contains an improper restriction of XML external entity reference vulnerability that could allow an unauthenticated, remote attacker to read sensitive configuration information on an affected system.
WHY THIS VERDICT Attacks are confirmed. The vulnerability is 83 days old, so many systems are likely still unpatched.
WHY IT RANKS HERE Exploitation is confirmed by an authoritative source. The confirmation is 1 day old. 6 products are affected.
- HIGHEST CONFIRMED RUNG
- EXPLOITED
- CISA KEV
- LISTED
- EXPLOIT CODE
- NONE KNOWN
How far has it climbed?
01 TALK
■ CONFIRMEDNEWEST EVIDENCE · 2 INDEPENDENT SOURCESCVE-2026-20320 discussed publicly (CIRCL sighting). CVE-2026-20320 discussed publicly (CIRCL sighting).
02 EXPOSED
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETWe have no source that counts exposed systems yet. Internet scan data needs a partnership we do not have. No evidence here does not mean nothing is exposed.
03 TRIED
■ CONFIRMEDNEWEST EVIDENCE · 3 INDEPENDENT SOURCESAttacks that worked are confirmed (step 4), so attempts count as confirmed too.
- SRC: CIRCL Vulnerability-Lookup sightings: Exploitation of CVE-2026-20320 reported (CIRCL sighting) · NOV 10
- SRC: CVE List V5 and CISA Vulnrichment: CISA Vulnrichment marks CVE-2026-20320 as actively exploited · NOV 10
- SRC: CISA Known Exploited Vulnerabilities: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability · NOV 9
04 EXPLOITED
■ CONFIRMEDNEWEST EVIDENCE · 3 INDEPENDENT SOURCESExploitation of CVE-2026-20320 reported (CIRCL sighting). CISA Vulnrichment marks CVE-2026-20320 as actively exploited.
- SRC: CIRCL Vulnerability-Lookup sightings: Exploitation of CVE-2026-20320 reported (CIRCL sighting) · NOV 10
- SRC: CVE List V5 and CISA Vulnrichment: CISA Vulnrichment marks CVE-2026-20320 as actively exploited · NOV 10
- SRC: CISA Known Exploited Vulnerabilities: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability · NOV 9
05 DAMAGE
□ NOT TRACKED YETNO SOURCE FOR THIS STEP YETBreach notices and filings rarely name the flaw that was used, so we cannot link them to this event yet. No evidence here does not mean no harm.
When each thing happened
- DISCLOSED
- EXPLOIT CODE PUBLICNOT YET
- FIRST ATTACK REPORT
- CISA KEV LISTING
- US FEDERAL DEADLINE
THE FIX
CISA's instruction: apply the vendor's fix, or stop using the product if no fix exists. CISA set Nov 24, 2026 as the deadline for US federal agencies. It is a US government deadline; use it as a guide.
Questions to ask this week
- Do we run Cisco BroadWorks? If yes, is it patched or cut off from the internet?
- Who owns fixing it, and by what date?
- Have we checked for signs of attack since the first report, not just since the patch?
How it unfolded
- Attack activity. NOV 9, 2026Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability
- Attack activity. NOV 10, 2026CISA Vulnrichment marks CVE-2026-20320 as actively exploited
- NOV 10, 2026CVE-2026-20320 discussed publicly (CIRCL sighting) (11 reports)
- Attack activity. NOV 10, 2026Exploitation of CVE-2026-20320 reported (CIRCL sighting)
- NOV 10, 2026Cisco BroadWorks and Openwave Flaws Actively Exploited Despite Available Patches
SOURCES
- [1] CIRCL Vulnerability-Lookup sightings: CVE-2026-20320 discussed publicly (CIRCL sighting), NOV 10
- [2] The Hacker News: Cisco BroadWorks and Openwave Flaws Actively Exploited Despite Available Patches, NOV 10
- [3] CIRCL Vulnerability-Lookup sightings: Exploitation of CVE-2026-20320 reported (CIRCL sighting), NOV 10
- [4] CVE List V5 and CISA Vulnrichment: CISA Vulnrichment marks CVE-2026-20320 as actively exploited, NOV 10
- [5] CISA Known Exploited Vulnerabilities: Cisco BroadWorks Improper Restriction of XML External Entity Reference Vulnerability, NOV 9
- [6] CIRCL Vulnerability-Lookup sightings: 10 more reports